Q:
I have two questions:
1. Recommended supply range is 4.5V to 5.5V - will the device operate at lower voltages (e.g. 3.3V)?
2. We would like to minimse power consumption by operating in a fast pulsed mode - do you know what the settling time is from power-up to valid analogue output?
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A:
answer1:
The datasheet guarantees all the tolerances for a supply voltage beetwen 4.5V and 5.5V.
But you can use the sensor with a power supply voltage under 4.5V. At 3.8V is a bend in the characteristic. Until 3.8V the attributes (sensitivity, offset and angle-error)
become worse but are still linear. Under 3.5V the 2SA-10 does not work anymore.
answer2:
The Power-On time is 400µs. After this time are stable output signals guaranteed (at 5V supply voltage).
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Q:
Many thanks for your helpful reply. The speed is fine for our application.
Do you know if there are any plans to introduce a lower voltage part in the near future?
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A:
There are no plans for a 2SA-10 version with a lower supply voltage in the near future.
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Q:
What is the resolution of the output X and Y of the 2SA-10?
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A:
It is an analog output i.e. the resolution is theoretically infinite.
In practice, it is of course limited through the noise of the amplifier.
If you use decoupling caps on both signals without adding a filter, you can achieve a resolution between 9-10 bits depending on the environment (noise on the supply lines,...).
However, if you add a filter (1st order i.e. simple RC or 2nd order...), then you can reduce the noise, increase the resolution while slowing down the whole system (reduced bandwidth). There, you can reach 12 bits.
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Q:
and how about the accuracy of 2SA-10 comparing with the MLX90316?
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A:
It is difficult to compare as the 2SA-10 delivers sine & cosine signals while the MLX90316 provides directly an angular information from 2 raw signals which are comparable to the sine and cosine signals of the 2SA-10.
Those raw signals have comparable accuracy although it should be mentioned the MLX90316 offers a larger compensation capability.
If you process the 2 signals from the 2SA-10 w/ an external circuit (ADC + CORDIC algorithm + linearity compensation), you should get similar results than the MLX90316 for which the signal processing is done on-chip in combination w/ EEPROM space for compensation.
In terms of figure, it is always worth separating the linearity error (at room temperature) and the thermal error.
The linearity error you can get from the MLX90316 is governed by the intrinsic linearity error (max. 1 Deg. over 360 Deg.) and the linearity error linked to the magnet position w/ respect to the IC. The MLX90316 provides a multi-point calibration which will lower the linearity error of the output transfer characteristic (the efficiency of this multi-point calibration is higher when the angualr stroke is smaller).
The thermal drift is mainly governed by the thermal offset drift. It will induce an angular drift of 0.3 Deg. Taking into account other contribution, the thermal error is limited to less than 0.5 Deg.
As mentioned earlier, this can be achieved w/ 2SA-10 using off-chip signal processing !...
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Q:
How is the Max intensity of magnetic field for 2SA-10. A distributor told me that it was 40mT, but in the datasheet, it was 80mT. Could you tell me which is correct ?
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A:
Datasheet is correct. Above 80 mT, the linearity error linked to saturation of the magneto concentrator will start increasing.
We usually recommend to work between 20 and 70 mT.
we can say that the target should be 45 mT in order to get a quite symmetrical tolerance window i.e. +/- 25 mT.
In this case, you should be safe over airgap, magnet, temperature tolerances...
Do not forget that a magnet gets always weaker at high temperature and stronger at low temperature...
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Q:
We have different sets of magnets, some work very well without producing error codes and others produce "ADC Saturation/Failure" and "Magnet Too Strong" error codes.
The "magnet too strong" error is pretty self-explanatory. If there are any details beyond the datasheet it would be much appreciated.
I have a few questions about the MLX90316BDG's ADC and gain control.
Can you tell me the optimal range of magnet field strength for the 'BDG?
Can you give me a little more information on what the primary cause(s) of the ADC saturation/failure error code?
If possible, a brief explanation beginning with the magnet would be great.
I'm also interested in details such as if magnet rotation speed precipitates the ADC error code.
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A:
The magnetic specifications are defined in the datasheet, pag 14, Section 11:
Magnetic Flux Density = 20 ... 70 mT
ADC value = Gain * B * S
Gain = Analog gain = Rough gian * Fine gain stage
B = Field ( mT)
S = Sensitiviy of hall plates.
Automatic gain ON -> ADC value = 90 % 14 bit, for a B = 20..70mT.
ADC saturation happens when the measured signal has reached the max digital value = +/- 14 bit. The root cause can be linked to
- Automatic gain is Off and applied field + gain setting is too high
- Automatic gain is ON and the applied field is >80 mT. This can be checked with the RAM values. The rough gain is probably at the lowest value = 0
- The magnetic field is changing much faster then the automatic gain control can compensate and creates an overflow. This can happen when the magnetic field density ( sqrt ( Bx^2 + By^2)) is not constant and is changing very fast.
The gain is updated typically every 3 ms.
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Q:
while i'm trying to configure the MLX90316,First,i clicked "new device",then i set settings, after this,while i want to modify the output DAC gain and offset,they are disabled,the default values are 1.000000 and 0.000000 respectively,if i click "characterize",it shows a messagebox"PTC-04 received from the chip ACK/ERR=FFH.while writing to adress 0072h". then i verified the connection,first time i go to the measurement screen,all parameters such as Vout,Idd,Vdd are ok.Then i quit MPT,powered off PTC-04,and started once again,but the same problem occured.
Do you have some suggestions about this?
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Q:
I've solved this problem but there is another one!
After programming 90316, i went to the measurement screen, the angle is veried while i rotate the magnet. but Vout is constantly around 0.5%Vdd.
I have read one FAQ before about the same problem.
and you gave some advice, i followed, but the gain and offset of DAC is about 1.2 and -1.026% respectively,not around 1.01 and -0.3%,how can i change these two parameters?
by the way, MY RG always equals 1,does it mean saturation?.
Thanks!
Best regards!
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A:
If Vout is stuck at zero volts, the chip could be in diagnostic mode. This could be caused by the magnet being too strong. See section 14.4.2 and section 15 of the datasheet for more information on Rough Gain and the diagnostic modes.
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Q:
i want a negative slope between 5.25 deg and 89.25 deg in my application with 90316,from the datasheet i learned that, only after point C the slope could be negative, so my settings are as follows: A_X is 0 deg, A_S is 0 %Vdd/deg,A_Y is 95%Vdd, B_X is 5 deg, B_Y is 95%Vdd,B_S is 0 %Vdd/deg,C_X is5.25 deg, C_Y is95%Vdd,C_S is -1.0119%Vdd/deg, while i input these valuse,and click write to EEPROM, a messagebox said"succesful" shew up,but while i click read eeprom,the slope after C point,it is 1.165, and the output is incorrect.
do u have some advice?
!
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A:
It is indeed correct that 90316/BCG can have a negative slope LNR_C_S.
If you use the correct software, i.e. UI 90316 BCG, then this should be possible.
I guess that you are using old UI 90316 BAD ?
Another possibility is to use the negative slope option in the UI or invert the rotating direction.
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Q:
When using 90316 in a PCB that has a MCU,how can i program 90316? Because the output of 90316 is connecting with the MCU, the Voltage of PTC could damage the MCU,how to avoid it?
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A:
Applications were the sensor is connected to a local MCU typically use the SPI communication protocol and there is no external connection to the 90316.
In this case you need to order the pre programmed 90316 - option SPI.
The 90316-SPI is pre-programmed as a 360 deg angle sensor with 2 x 14 bit output data.
Programming the 9016 is not needed since you have all the information. ( 360 deg = 14 bit)
Programming in these applications is not feasible since
- You need 7.5 V and this is not possible without a protection circuit for the MCU
- You need external connection that will only be used for a 1 time programming = more expensive
- You need to protect the external connections for ESD = more expensive
If extra calibration points are needed, then this information will be stored in the MCU that most likely has a lot of space left, since for a 360 deg application the number of calibration points in the 90316 EEPROM is limited.
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Q:
I have a question regarding the operation of the switch output on the MLX90316 sensor.
In normal operation, the switch remains open until a certain angle is reached. After this angle, the switch closes. For our application, we need the behaviour of the switch to be reversed.
I have been told that this should be possible by programming the 90316 device in the correct manner. I have however, had no success with this.
If anyone can shed some light on this, I would really appreciate that!
Thanks for your time.
Nik
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A:
There is no optional EEPROM setting to invert the functionality of the switch.
The only option is to
- Invert the rotating direction, but then also the analog output is inverted so probably not useful.
- Add an external transistor to invert the switch.
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Q:
Thank you for your reply. We managed to get the switch to function the way we want. As you said the rotating direction must be inverted so that the measured angle is decreasing with a positive rotating direction. By programming the sensor in reverse, ie from Point D to Point A, we were able to maintain a positive slope output.
So, it is indeed possible to make the switch work in an inverted fashion, but I now have much less hair than I did a couple of weeks ago.
Thanks again for the help.
Nik
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Q:
I have the MLX90316 LCD-BDG model. So I'm going to use PIC16f874 and Circuits as shown in Fig.18 from Datasheet. Also, the circuit components in the first line of Table 3 are used.
However, I'm confused because of programming. I don't know whether the master should only send AAh and FFh or AAh followed by 9 bytes FFh to the slave. In addition, do master and slave are operated at the same time ?
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A:
- The circuit shown on fig 18 is for non SPI version. Since you use MLX90316 LCD-BDG, i.e. SPI version, you can also use circuit shown on fig 16.
- The timing diagram on pag 29 should help to understand the protocol.
MOSI is what the master needs to send, and MISO is what the chip will answer. Since we use a common line, the result on pin 5 of 90316 will be the combination of both.
The master need to send the 10 CLK bytes, and during the first CLK byte it needs to send AAh ( or 55h if you use the inverter). Next you keep the line high, so that you can see if the chip answers.
The master will therefore send 2 start bytes , and then keep the line high for the rest of the protocol, and this is the same as sending AAh and keep the line high ( = 9 x FFH) for the rest of the protocol.
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Q:
Are there any waveform traces of a transation between the MLX90316 and a master spi device that can be posted here?
The data sheet on the part does not specify setup and hold times for clock and data, and it would be very useful to see what a successful transaction looks like.
If not, would it be possible to send in a waveform transaction to you to get a diagnosis of the issue?
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A:
All the timings and conditions are explained in the datahseet , pag 28.
The most common mistake made is the sending of the start byte. The 90316 expects to receive AAh + FFh, @ falling edge of CLK. ( this is what you should see on the scope at pin of 90316) If you use an inverter to send the data, then you need to send 55h + 00h.
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Q:
I am trying to write a calibration program(use C) for production line.
I follow the procedure showed on PSF090333AAMLX.pdf page 28.
But i got(maybe) problem on the step of SetAlphaMiddlePos.
How can i check that?
Is there any method that i can use ?
i used the scope to check the signal while i traced my program.
Yes, it works but i do not know the signal's meaning.
Is there any C sample code that i can reference ?
Inside the PTC-04 CD , i only found sample code for VB(excel) & Labview.
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A:
We currently do not have an C example for the 90333, but we can help you with the code if you encounter problems and send us more details.
If "SetAlphaMiddle" maybe gives problems, I assume that you did not receive an error message which indicated that there was no problem. The result of the SetAlphaMiddle funcion should be noticeable through the EEPROM parameters CodeALPHAX & CodeALPHAY. CodeALPHAX should correspond with the magnet position and CodeALPHAY with the requested output.
If you received and error message, then please send us the used code and error message.
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Q:
reading the datasheet I'm not sure what the numbers read from SPI represents: SPI_Byte<2:1> (alpha) is a voltage or an angle? (same for Beta)
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A:
The SPI data is a 16 bit value corresponding with Alphaout and Betaout. The relationship between alphaout and alpa ( resp. Beta) is defined with the LNR parameters, identical to analog or PWM mode.
So the 16 bit data corresponds with a 100 % output range, and the slope = ... % / deg depends on the programmed LNR slope parameters and clamping levels. See also datasheet pag 22/23
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Q:
I wonder if I can make a testing/programming software in order to program some parameters customized device by device: i.e. center position, max upper pos etc. Is there anything available on your side?
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A:
Melexis provides the PTC-04 programmer and software for this purpose. please contact your local sales or distribuition representative for details.
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Q:
I have to implement a small joystick (8 positions) plus button depressed (joystick is idle, magnet pushed near the sensor). I wonder if I can use the 90333 configured as XYZ and then: calculate by host microprocessor the position, get the pressbutton info via the amplitude of Z. Is this feasible?
How can I calculate the position from XYZ?
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A:
- The 90333 can be used in a XYZ configuration if you use the SPI output protocol.
Through SPI you will receive the digital value of X,Y and Z, and the angle can be calculated as Atan (Z/X ) and Atan (Z/Y).
- Keep in mind that there is normally an automatic gain adjustament, but since you are inbterested in the absolute value of Z, you may need to disable this or check for relative changes of Z. ( Z = Bz * Gain) .
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Q:
I want to use the MLX90333 sensor for measuring the absolute strength of flux density. Therfore I will use SPI mode with XYZ=1. Reading the knowledge base I found out that I will have set DisableGainCtrl to 1 to disable the AGC. But how will the X,Y,Z values read out from the MLX90333 be coded. Will it be signed 2´s complement (1.15 format)? Meaning: 0x7fff +FS (+70mT) and 0x8000 -FS (-70mT)? Will the smaller Bz values be corrected automatically by the default settings of KZ and KT? Will it be possible to measure low flux densities e.g. what will happen if flux density goes below 20mT? Thank you in advance for your help,
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A:
Even if the AGC is disabled, the sensitivity is not known. For absolute flux density measurements, you must first calibrate the sensor output in a known field.
The measurements are in 2s complement as you described. You can measure lower flux densities, including zero. You should also set ResOnFault=0 to avoid entering a fault mode if the field is too large or too small.
The Kt correction has no effect on the Bx, By, Bz. I don't know if the Kz correction is applied to Bz, perhaps one of the designers will answer this.
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Q:
Does Melexis have equivalent for Allegro's ACS712 current sensor?
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A:
The Melexis CSA-1V is equivalent from the application point of view. However, the ACS712 has an integrated current conductor in the SO8, meaning that the current to be measured flows through the pins of the package. Whereas our CSA-1V measures the field generated by the current that flows in the Track of a PCB or in a external buss bar. This makes a more truly "isolated" current sensor.
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Q:
Are the individual magnetic components available. If so how are they available. Also what is the range of the hall effect sensors inside the chip and can this be changed.
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A:
The 90333 is an integrated device. It does not use individual Bx,By and Bz sensors but uses a patented system to measure all 3 from the same chip. For more detail contact Melexis directly.
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Q:
We are trying to develop a control system for tower crane. I would like to get the angle of rotation of the tower crane. Kindly teach me which is good magnetic angle sensor that i can attached to the motor.
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Q:
in principle for absolute rotary position sensing Melexis can propose the MLX90316, which is a Rotary Position Sensor and which allows to measure the angular position of a magnetic field. However, in order to know if the MLX90316 is really the best solution, more information about the final application are needed. In order to get more information on the MLX90316 you can download the dedicated datasheet on this website.
For further support don't hesitate to contact us again.
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Q:
where to buy it?
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A:
click the contact link on the top of the page (www.melexis.com/contact.aspx) and select your country in the drop down menu.
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Q:
I continue to have issues with pin 7 drawing a lot of current. It seems the device is failing due to some transient either on the ground or supply voltage. Would the device operate if pin 7 were pulled to VDD through a resistor instead of being tied directly to the 5V supply? I'm hoping that if the device fails (at pin 7), the resistor will limit the current, and the rest of the device may continue to work. ??
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A:
We haven't experienced any specific problems with the pin 7 pulled directly to VDD. If the device is connected as proposed in the connection diagram in the datasheet, everything should work properly and the current consumption should be around 15mA. The capacitor between VDD and GND should be placed as close as possible to the device. You can try to put a resistor (5 to 10 kOhm) between pin 7 and VDD, the device will continue to work. If the problem will persist you could send me the schematic of your application.
Angelo
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Q:
Does Melexis have current sensor? If yes, is there a cross for LEM make DHAB S/14?
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Q:
Yes there is CSA-1V.
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Q:
Hello,
Does Melexis have cross for current sensor DHABS/14 from LEM.
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A:
We do not have similar current sensor modules like the DHAB S/14.
What Melexis offers are sensors which can be used to measure current, but not the whole module.
For example the MLX90251, datasheet:
http://www.melexis.com/prodfiles/0004765_MLX90251_009.pdf
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Q:
I am applying a 90316 and 90215 that will require a custom manufactured Neo magnet. Does anyone have any recommendations for custom manufacturers (not distributors).
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A:
Please see the last page of the Magnet Application Note MLX90316.
We have a list of magnet manufacturing companies, all of them offer NdFeB and/or NdFeB bonded magnets.
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Q:
we’re programming the MLX90316 BCG with the PTC04. We want to switch the programming signals and VDD for the chip with relays. (Without the relays, everything works fine.)
With about 10% of all trys, there occur errors when calling programDevice(), sometimes when calling SetRoughGain(): the DLL returns an error. I did not find a function which gives more information than the return value representing ERROR....
Now I wonder what happens if I just call the failing functions again... Calling SetRoughGain() twice might not be problematic at all, how about programDevice()? I tested it twice, it worked both times. Can it be guaranteed that when I call programDevice() and it returns NO ERROR that the device is programmed correctly? Does that function read back what it wrote?
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A:
Programming the 90316 should always work. If it is connected directly or through a relay, the programming should be the same. On the daughterboard we also have relays to switch the output, so I do not see any reason why it should create yield losses if you add a relay. Of course when you switch the relays, you should be sure that there is no bouncing when the communication starts. Maybe the extra cabling creates some voltage drop or parasitic capacitors and the timings or levels are not correct any more.
What maybe could help is to use sense lines, or reduce the baudrate (4800) or increase the programming level to Vprog=8V and check if it helps.
To answer your question: When PTC-04 writes to the 90316, then we send the write command + data + crc ...and the device will always answer and send an acknowledge byte to confirm that the command was accepted and processed correctly. If for any reason the device does not understand or does not accept the command, then there will be an error. Typically the error message will be;: Wrong ACk byte or missing ACK byte So yes, if you do not get an error, then the device is accepting the command and confirms that it is programmed correctly.
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Q:
Does Melexis have IC which can be used for Digital Compass application?
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A:
At the present time we do not have such an IC. It is among many items we investigate at R&D level but there is no standard product planned in the near future. Please check back in 6 months for an update. If you are interested to explore dedicated developments in this area you may want to contact your local sales representative or Sales Area Msnager. Please look to the "contacts" section of our website for the name of the nearest Sales person/organization.
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Q:
I'm using the EVB90316 evaluation board and I'd like to know which type of the MLX90316 is used here and what's the operating temperature range. Although I have the data sheet, however I cannot find these information.
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A:
The evaluation board is equipped with the following version of 90316:
MLX90316 K (- 40°C to + 125°C) - PPA
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Q:
One of our Customer isLooking for an equivalent of Micronas P/N HAL506UA-A.(TO92 Pkg)
Temp:-40-+150 Deg C.
Customer wants Melexis a Suitable Magnet for this Application.Suggested US 5781,but Temp Specs does not comply.We solicit your Kind advise.
QTY: In Excess of 100K per year.
Major
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A:
Hi Major,
US5781LUA and also US5782LUA are the alternatives. They both have a temp spec of -40° to 150°C. Why do you think the temp spec does not comply?
Kind regards,
Tanguy
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Q:
I'm with a medical device company and have an engineering requirement to sense when a person steps on a plate and when they step off. The problem is that the total displacement that has to be measured is about .030 to .060 inches. Is it possible to accomplish this with a hall switch? How does one overcome the hysterisis?
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A:
If there is application when you need only two states (on/off) then you can use hall latch like US1881,2881,...
Then you have two possibilityes. You can use permanent magnet and adjust distance betwen hall switch and magnet, or you can made a coil but you need very accurate current source. In this case your distance can be constant and you adjust sensitivity with current!
The first option is cheaper. Current source can be made with a few transistors for second option.
The third option is that you took pre-programmed linear sensor like MLX90215LVA-BC03 (10mV/mT). In this case you must build external hysteresis circuit(one op-amp)and you can adjust it with two resistors(loop)! Here you can also use permanent magnet!
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Q:
I recently purchased a US 4881 LUA Hall Effect Sensor IC. I am trying to use it for speed sensing by having a magnet rotate with my rotational shaft, and the north and south poles of the magnet will trigger voltage pulses to my microprocessor.
The problem is that my microprocessor is based on TTL logic and it requires close to a 5 V to register a logic high. The output I get from the Hall Effect Sensor in the presence of the magnetic field is only 0.5 V (i.e. the sensor's output ranges from 0 to 0.5 V). This seems to be the same regardless of what supply voltage I provide and how close I move to the magnet to the sensor.
I was hoping not to have an amplifier stage in between the sensor and teh microprocessor. Any ideas?
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A:
It looks like you are not using a pull up resistive load to 5 V.
The US4881 has an open-drain output (low-side). It means you need to put a resistor to 5 V to get a 0 - 5 V logic signal out of the sensor.
It should work right away. No need to put an amplifier.
Otherwise, the part has been destroyed in a previous step but I guess you have tried multiple part w/ the same result.
Note: what speed do you want to measure ? What is the RPM of the target and how many pole do you have on your magnet ?
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Q:
My 97 Harley Sportster has a speedometer sensor and a cam position sensor. Are these type of sensors Hall Effect types? If the speed sensor is, can another test ckt. be connected to that sensor, and still have the speedometer operable? The Harley repair manual gives directions on making a test harness which would connect (T-off) to the speed sensor? Would connecting other circuitry in this manner cause damage to the sensor?
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A:
They may be Hall effect sensors or variable reluctance (VR) sensors. If the signals are digital (0 and 5/12 volt pulse train) then they are probably Hall sensors. If they are Analog and range from millivolt at low speed to 100's of volts at high speed then they are Variable reluctance. The Hall sensors should be easy to measure with any oscilloscope but the VR sensors will need some inteface circuit to prevent damage and signal degradation. check the shop manual for more details, this is a bit out of our normal FAQ range!
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Q:
I need a Hall IC capable of sustaining 20KV DC all the time...
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A:
The 20KV often specified is refering to an ESD pulse. This is a very short electrostatic discharge that could kill an IC. WIth the proper external protection it is possible to survive 20KV discharges.
|
Q:
I'm relatively new to your products and need a recommendation.
I am interested in several applications and would like to know which device to use for each:
1) Substitute for a potentiometer (analog output)
2) Substitute for an encoder (digital output)
Is there any way to use a simple Hall switch, or do these applications need to be done with a programmable device?
Thanks
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A:
In substituting for a potentiometer the analaog products to consider include the MLX90215, 90251 or 90242. Other products to consider from our sister company, Sentron, would be the 2SA-10. All of these devices require some permanent magnet field source to drive the output through the desired range for the desired mechanical displacement. See our Hall effect applications guide for more details.
An encoder with digital outputs can be realized with a simple Hall effect digital switch or latch like the US188x,288x, 588x or even the MLX90224. All of these devices will require an appropriate multipole ring magnet to create the multiple pole transitions per revolution needed to implement an encoder function. There are also some ideas on this in the Hall applicaitons guide at www.melexis.com
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Q:
I'm searching for a hall sensor (digital switch, unipolar), which can be used at high ambient temperatures until 160°C (200°C).
Is it generally possible zu get such a sensor? Most of them are only specified until 150°C.
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A:
As you noted, most of the Hall sensor are specified for a maximum temperature of 150 degree Celcius.
This generally means the device has been designed, characterised and tested for such temperature of utilization.
If you go above this maximum temperature, you exceed the absolute maximum rating which leads to :
1) reduction of device lifetime reliability; for example increasing 30deg above the maximum rating can reduce the device lifetime by 10.
As you see, increasing the junction temperature is quite critical. Some hall sensors manufacturers define higher maximum junction temperature like 175deg guaranteed for few hours like 1000h, which is a bit tricky as you do not have information of the device parameters at such temperature.
(you can also find more if you want in lots of white papers related to device lifetime reliability depending on junction temperature)
2) Risk of parameters drift at very high temperature; since the design target is 150deg maximum, the device performance cannot be guaranteed above this temperature. The worst case is if there are drift which could cause an application failure. This requires extended application test and validation.
3) Risk of over-heating stress damage due to exposure to high power dissipation
It should be considered very carefully if the investment and risk is worthwhile.
We could analyse your needs by knowing more about the final application, and maybe propose a better alternative.
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Q:
Does Melexis have a hall switch which will work with both North and South Pole simultaneously?
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A:
Yes, the part number is MLX90248.
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Q:
Can anyone please direct me to the Melexis Hall-Effect Sensor Design Kit referenced in the Hall Effect App. Note? Is it still available? Thanks.
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A:
This design kit is out of production at the present time. It mainly consisted of a few sample Hall IC's along with a few different Neodymium magnets. Did you have a specific requirement for one of the magnets or one of the IC's from the Kit? We may have some of the constituent pieces still available but I regret to say we do not have the Kit as described in this application note.
|
Q:
Can you help me in finding cross for Honeywell's hall effect digital position sensor.
Part No. for honeywell sensor is SS513AT.
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A:
The US1881 - Hall effect latch is the most suitable device to replace the Honeywell.
Here are the characteristics in brief :
- Bop = +5mT typical / Brp = -5mT typical
- Supply Voltage : 3.5V ~ 28V
- Supply Current : 5mA maximum
- Open drain output (Sink)
- Output voltage : 0.5V max
The device is available in several temperature specification. The "L" specification (-40~150deg) is like to Honeywell part.
The packages proposed offer possibility for through-hole (UA package) or surface mount (SE package).
The main difference is regarding the packaging as we do not deliver the same package as Honeywell.
Please refer to the datasheet on our website for more detailled technical information.
|
Q:
Hello,
see the below
********************
CodeAGC=115 Enable automatic gain control
(MLX90316BF/CxL)
(pls see Page67 of PTC04_PSF_MLX90316.pdf)
********************
I can sucessfully set
CodeDRESONFAULT with the DLL method "SetEEParameter"now,meanwhile cannot set 'AutoRG',whose paramID is 115,correct?
what's wrong and how to set it?
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A:
- CodeAGC (115) is only applicable if ypou use 90316Cxx, i.e. chipversion =5,7,8.
Since you are using chipversion = 3 or 6 , BAD or BCG, the equivalent parameter to program is CodeERGAOFC=1 and maybe CodeARGC during the startup of the chip.
You can check datahesheet for more details.
|
Q:
Thanks for you immediate response.
I've just tried to set paramID=62 (CodeERGAOFGC,i.e. Rough Gain Adjustment On Fine Gain Clip) of my 90316BCG as you instructed me,but there is no effect ,
Meanwhile the invoking to set or reset paramID=72(Automatic Rough Gain Control @ startup)does work well,
I think I can verify the above with my 'Meleix Programmable Toolbox'.(click the button of "Read EEPROM" and "Move ROM to Temp")
If you open your own Toolbox,
you may find out this 'AutoRG' belongs to the "Calibration and Debug Modes",which is different from CodeARG;
Dose these "AutoRG" here is just equal to 62?
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A:
You should be able to verify all the parameters.
In the UI90316/EEPROM you will find AutoRG , DisableFG and ARGC, which corresponds respectively with PSF parameters CodeERGAOFGC , CodeDFINEGAIN and CodeARGC.
CodeERGAOFGC , CodeDFINEGAIN are indeed in the debug mode, because we recommend to use the automatic gain but it is possible to switch it off for debugging.
The AutoRG ( CodeERGAOFGC ) will only work if the fine gain is NOT disabled.
The CodeARGC is only active during the startup, and then the automatic gain is defined by CodeERGAOFGC. Therefore the staring value of the rough gain ( Rgain) is important and depends on the other setting.
There are actually 2 possible scenarios:
If the magnet is present during programming
CodeERGAOFGC = 1
CodeDFINEGAIN = 0
CodeARGC = 0
CodeRoughGAIN = correct starting value from SearchRG
If the magnet is not present during programming, but it will of course also wok with magnet
CodeERGAOFGC = 1
CodeDFINEGAIN = 0
CodeARGC = 1
CodeRoughGAIN = 0 ( lowest gain to prevent saturation)
Please check also latest datasheet for detailed description of the Roughgain.
|
Q:
I've just run my Labview program to call the "SetEEParameterCode" in order to Set or Clear DisableFG, My Melexis Toolbox has verified it works well.
But the operation over "CodeERGAOFGC" have no influence on "AutoRG"bit.
Is there any necessary step ignored by me?
|
Q:
I think the above strange problem has been resolved.
Thanks a lot for you help.
|
Q:
Could you help me to check the below:
1) "Reset On Fault" . I am referring to one item of "Calibration and Debug Modes"
of Melexis Toolbox ,its EEParamID=52, i.e. CodeDRESONFAULT=52 ;
2) Since it is named as "Disable Reset on Fault "@ Page65
of "PTC04_PSF_MLX90316.pdf",it will function ONLY when this bit is cleared
(bit=0).instead of set(bit=1)
correct?
|
A:
1) There are 2 parameters that are linked to the diagnostic modes, `( datasheet 15. MLX90316 Self Diagnostic, pag 25:
In case of an error, the output will be switched to diagnostic mode.
The CPU Reset itself immediately or after recovery of the error
- CodeDRESONFAULT , ID = 52
- CodeDOUTINNFAULT, ID = 106
2) Indeed, you can disable these option by programming both parameters =1 and enable it by setting the value to 0.
|
Q:
In section 16.10.6 of the datasheet of the mlx90316, it states that if there is an error in the part, the miso pin will stay high impedant. How can one tell if the part is not responding due to one of the internal errors or something else. Can the device be queried for the firmware code, etc?
|
A:
In case there is a serious problem, like ROM CRC error, EEPROM CRC error,etc, then the sensor will reset itself. In this case there is no possibility to check / communicate with the device and it is indeed not possible to see the difference between an internal error and for example a broken pin connection.
|
Q:
I have MLX90316 sensor and now I would like to program this sensor using DLL LIB under LabView (with PTC-04). I have found some example on CD for the LabView but there are no SPI Mode (only Analog(2) and PWM(5-7)). I am using Demo_90316_solver_PSF.llb Can You any tips how can I solve this problem. Thanks
|
A:
To enable the SPI mode in the solver :
SolverSettingOutputType = 2 ( = SPI, in the example only 0 or 1 is used )
SolverSettingOutputMode = n/a
or if you want to program the device as a defsault 360 deg SPI sensor, then the following example can also be used
( the code is in VB, but simular in LV)
PSF90316.SelectedDevice = 1 'Select Die 1
PSF90316.Advanced.ChipVersion = 3 'Set type to BAD
PSF90316.DeviceReplaced 'Reset software settings
PSF90316.ReadFullDevice 'Read EEPROM from chip
' Set EEPROM paaramaters in cach
Call PSF90316.SetEEParameterCode(CodeHS, 1) 'Enable HS
Call PSF90316.SetEEParameterValue(CodeCLAMPLOW, 0)
Call PSF90316.SetEEParameterValue(CodeCLAMPHIGH, 100)
Call PSF90316.SetEEParameterCode(CodeLNRAX, 0) '= 0 deg
Call PSF90316.SetEEParameterCode(CodeLNRBX, 65535) '= 360 deg
Call PSF90316.SetEEParameterCode(CodeLNRCX, 65535) '= 360 deg
Call PSF90316.SetEEParameterCode(CodeLNRAY, 0) '= 0 %
Call PSF90316.SetEEParameterCode(CodeLNRBY, 65535) '= 100%
Call PSF90316.SetEEParameterCode(CodeLNRCY, 65535)
Call PSF90316.SetEEParameterCode(CodeLNRS0, 8192) 'slope = 2000h = 100%/360deg
Call PSF90316.SetEEParameterCode(CodeLNRAS, 8192) 'slope = 2000h = 100%/360deg
Call PSF90316.SetEEParameterCode(CodeLNRBS, 8192) 'slope = 2000h = 100%/360deg
Call PSF90316.SetEEParameterCode(CodeLNRCS, 8192) 'slope = 2000h = 100%/360deg
Call PSF90316.SetEEParameterCode(CodeDP, 0) '0 deg point
Call PSF90316.SetEEParameterCode(CodeDRESONFAULT, 0) 'enable reset in case of error
Call PSF90316.SetEEParameterCode(CodeDOUTINNFAULT, 0) 'enable reset in case of error
Call PSF90316.SetEEParameterCode(CodeERGAOFGC, 1)
Call PSF90316.SetEEParameterCode(CodeARGC, 1)
Call PSF90316.SetEEParameterCode(CodeFHYST, 0) ' disable hysteresis
Call PSF90316.SetEEParameterCode(CodeSPI, 1) 'enable SPI
PSF90316.ProgramDevice
|
Q:
Is it possibile to measure field up to 300mT with MLX90215EVA? And what about preprogrammed linear hall sensor MLX90215LVA-BC03(10mV/mT)?
|
A:
Yes it is possible if you are only going to measure a single polarity field at 300mT. The offset (Voq) can be programmed to 1v or less and allow a signal span from 1v to 4v. This would result in the +300mt * 10mV/mT= 3V signal being within the span of the device. IF the field is of opposite magnetic polarity the arrangement could be swapped by setting the invert bit or by setting Voq to 4 volts or even by applying the field to the back of the VA package.
The standard device MLX90215LVA-BC03 would not work because the offset is programmed to 2.5v and only allows a signal span of approximately 2 to 2.4 volts in one magnetic polarity. So a field of +300mT would be clipped at the upper supply rail (practically speaking about 4.5 to 4.9 volts) . In this case it would only be possible to sense about 200 maybe 240mT when using the MLX90215LVA-BC03.
|
Q:
I am looking at a new design using the 90316 chip/magnet combination and need some information on the setup.
- What would be the best magnet to use based on an operating range of 150° , gap of between 1.5mm and 2mm and a temperature range of -40°C > 160°C. The magnet diameter would preferrably be below 8mm.
|
A:
The 90316 requires a diametrical magnetized round or square magnet, with a min diameter of 6mm. For 150C I would advice a material with lower TC ( 200..300 ppm /C). Since the airgap is between 1.5...2mm, select the material and thickness of the magnet in such a way that the magnetic field strength at chip level is +/- 50 mT.
|
Q:
Based on the specification of a nominal desired magnetic flux density of 20-50 mT it seems that the quite small (<.250" diameter, .125" thick) SmCo magnet with a reasonable air gap (.03-.05") will achieve the desired flux density. Based on this please help me with the following:
1. What material do you normally recommend for the magnet?
2. Approximately what diameter and thickness is good for a typical application?
3. Do you have recommended magnet suppliers?
|
A:
answer1
Recommended materials: Neofer (plastic bonded NdFeB) => good magnetic characteristic / all shapes are possible / cheap
Also possible:
NdFeB => good magentic characteristic
SmCo => good characteristic over a wide temperature range
answer2
Have a look at Magnet Application Note MLX90316 on www.melexis.com
link:
http://www.melexis.com/prodfiles/0005221_ApplicationNote_90316_Magnet_Rev001.pdf
answer3
Recommended magnet supplier: Magnetfabrik Bonn www.magnetfabrik.de
Further suppliers are published in the Magnet Application Note MLX90316
|
Q:
My customer would like use MLX90217 for cam sensor and Mlx90254 for crankshaft sensor. And they don't very clear how to select magnet for these two chips. They ask for the documents about magnet selection for Mlx90217 and Mlx090254 and give the magnet and airgap vs. output signal curve. Would you please help me with this request?
|
A:
Your question lacks some important details. The gear target geometry is equally important to the airgap vs. output signal curve.
A typical magnet for use with the MLX90217 or MLX90254 might be something like a NeFeB material, grade N35 or better and in a 5mm dia. x 8mm length. A rare earth SmCo material would also work and might give better temperature performance especially above 125C, although a good, quality supplier of NeFeB would have grades of Neo materal to meet high temp requirements. I also encourage your customer to read thoroughly the datasheets on the products to better understand how magnet selecion affects performnce
|
Q:
i have two questions about MLX90316:
1.how can i realize mass download the routins to devices without PTC04 while mass production?
2.as stated,the total linearity error@25 Centigrade is +/-0.82 deg, i'm not sure it's an absolute error or not. That is, does it mean that during the whole span(360 deg) the error is +/-0.82 deg,and if it is ranging from 0 to 90 deg, then the error will be quarter? or it'll be constanly +/-0.82 deg whatever the measurement range is?
|
A:
1) Programming the 90316 is only possible with PTC-04. This programming tool is suitable for mass production and has already been used in mass production by many customers for many years.
2) The total Intrinsic Linearity Error of 90316 = +/- 1 deg ( See datahseet pag 13. This means that over the complete 360 deg angle span @ 25 C, the maximum accuracy error is +/- 1 deg. ( +/- 0.82 is an example from the AN Front-end Calibration)
If the device is programmed for a 360 deg application, and you use only 90deg, then the error specifications will remain +/1 deg.
However, by using the multi point end-user calibration, this error can be improved. The error will decrease with increasing number of calibration points.
For more information, please check AN Back-end calibration , Pag 4.
For every calibrated point, the error at that position will be almost 0 deg, and the effect will be maximum if the distance between 2 points < 90 deg.
Example: 90 deg with 3 calibration points -> Lin error < +/- 0.3 deg
|
Q:
in fact, i'm not sure about mass production,how to operate? i just read some materials about MLX90316 and PTC04, but i haven't seen PTC04 yet, and it'll arrive tomorrow. So i'll learn about it myself, and i'll ask for more info whenever i meet difficulties.
Best regards
FISH TAIL
|
Q:
I'm looking for a ratiometric Hall effect IC that can measure up to about 5000 Gauss. Is there such a device in your product range?
Sincerely
|
Q:
the MLX90251LVA-3 (i.e. Option Code 3) could be an option for you. This chip is a programmable Linear Hall Effect Sensor with Ratiometric Output voltage, which allows to measure magnetic fields up to 5000Gauss (=500mT) and even more.
|
Q:
Can I use the MLX90215 or MLX90251 ,with a cylindrical magnet, to measure rotary angle and have a linear output with regard to the angle?
|
A:
Not easily, the MLX90215 and 90251 are Linear Hall effect Sensors. Meaning their output is linearly proportional to the strength of the sensed magnetic field. Unfortunately to obtain a linear relationship between rotation and magnet field strength is technically challenging. Magnetic fields are not linear and need fairly complex magnetic pole pieces and magnetic circuits to create linear fields even over relative small rotational displacements. And many of the best ideas are covered with patents.
The MLX90316 is specifically designed to simplify this challenge. It uses Triaxis(Registered Trademark) technology to make it possible to use a simple disk magnet and achieve 360 degree rotational sensors. Through simple programming it can also do small rotational angles as well.
|
Q:
Where can I get a new 4-SIP-VA Socket for the PTC04 TestBench? Our socket is unfortunatly damaged!
|
A:
This socket is made by Loranger. P/N 02950-041-6215. Here’s a link:
http://www.loranger.com/
You'll probably have to check with Loranger to find a distributor.
|
Q:
Does this device have a default value for the gain when not programmed, as it comes from the factory?
|
A:
90215: All programmable values are by default = 0, because the 90215 has programmable "zener-zap memory cells", but this ZAP function is a one-time function and cannot be erased. See datasheet pag 3 for more information.
|
Q:
I'm looking for a Hall effect sensor with high sensitivity. MLX90215 seems to be matched most. However, for an application of measure the distance from magnet, I need to reduce the peak to peak noise.
I would like to work at 140mV/mT sensitivity. The noise will be 50mV. I'm thinking to set a low-pass filter at the output of sensor. However, I don't know which frequency I should choose. Could you please tell me the frequency of the noise at the output of this sensor?
Is there a better solution for this problem?
|
A:
Low pass filter can only help and the lower the cut-off frequency, the better results you will get.
At the sensitivity range you are thinking i.e. 140mV/mT or 14 mV/G, the internal sampling frequency of the chip is already pretty low (4 kHz) and therefore a cut-off frequency of 500 Hz (or less) for your filter will be adequate to eliminate the noise components which are associated to the internal sampling.
You can also work w/ MLX90251 as this IC has also an on-chip filter you can set through the programming unit (e.g. together w/ offset and gain settings). Using the strongest filter (i.e. Filter = 15), you will already get a serious noise reduction and you may not need an external low-pass filter: a decoupling cap will be enough. Advantage of MLX90251 is that 140 mV/mT is not at the top end of its specification while MLX90215 gain settings is somewhat limited to this value.
In any case, all those filter (internal or external) considerations need to be checked vs. your bandwidth requirement for your application. If you do not have specific "speed" requirements, you have the complete freedom. If you have speed/response time/bandwidth requirements, then you need to consider those while dimensioning your filter.
|
Q:
Where is the datasheet for the pre-programmed MLX90215LVA-BC03.
|
A:
Hello,
The preprogramming for BC03 is as follows:
- Sensitivity: 10mV/mT
- VOQ = 2.50V
- TC= 350ppm/°C
- No clamping
|
Q:
I'm interested in programming the MLX90215 manually so that I can use it in RAM mode, although I realise that this 'is not intended for regular operation'!
Is there any more information about the programming waveforms, transfer rate and timings and so on? The datasheet and the FAQ are quite sketchy.
|
A:
Is it for evaluation in the lab or to be used in a real application around a micro-controller (for example)?
In the first case, you should buy a MLX programming unit (e.g. PTC-04). It is delivered w/ all the necessary tools to program this part as well as other MLX programmable Hall sensors. It is a quite universal tool.
In the latter case, Melexis does not recommend this mode of operation as it was not the intention to let the device work permanently in RAM. This RAM mode is only for calibration purpose in conjunction w/ the programming unit i.e. in a well under-controlled environment. There is not enough check to guarantee this mode in a not-controlled environment (e.g. EMI perturbations,...). Furthermore, the programming protocol is based on "exotic" waveforms on the supply line (up to 15 V) and the output line. You will need to add dedicated H/W to make this happen.
In summary, we do not disclose the programming protocol for the MLX90215 and we recommend to use the ptc-04 in all cases.
|
Q:
It's for a real application in a lab :-)
I'm part of a group of physics students spatially profiling magnetic fields by scanning them with a Hall probe, and we chose this device because
a) the position and the size of the Hall plate is specified
b) we were hoping to be able to reprogram the sensitivity/range with the device in our apparatus
Unfortunately our budget is quite limited. We were prepared to build a small amount of dedicated hardware to facilatate the programming, but if it is only possible with the PTC-04, I guess we will be using a selection of pre-programmed devices.
|
A:
Do you want to build a permanent setup or do you plan to use it only for a small period of time ?
We could arrange something like a temporary loan ?
Where are you located ?
|
Q:
i am using MLX90217 hall effect sensor,i wanted to know,how much will be the maximum distance between sensor and magnets,and how can we convert the analog signal to digital output,if the rotation is high can the sensor able to get magnetic field.
I n the example it was mentioned that the magnet was attached to the back of sensor (non marked side )is it compulsory,i think the magnet has to attract the sensor ?
|
A:
Hi, sorry for the late reply.
Prior answering your specific question, I would recommend you to look at the other Posts linked to the MLX90217 as there are precious information there.
From your message, I have the impression you plan to use the MLX90217 at the front of a rotating magnet. It can work that way of course even if the most common application is w/ a so-called back bias magnet (magnet at the back of the IC) and a ferrous rotating target at the front of the IC/magnet.
The IC senses the magnetic flux density and from the modulation of this flux density, it derives a digital output signal. The output transfer characteristic is based on track-and-hold circuit and the hysteresis for the peak detection is the value in the specification i.e. 1.8 mT up to 10.0 mT.
The modulation of the flux density can be generated by a spinning magnet (like you are doing apparently) or a spinning ferrous target at the front of the IC w/ a back bias magnet.
|
A:
I have the impression that your are not using the right component for your application. MLX90217 is a gear-tooth sensor w/ track-and-hold circuitry. I do believe you need a simple Hall effect switch w/ fixed absolute threshold. Could you tell a bit more on your applications.
|
Q:
Hello, i´m interested in the MLX90217,to use it in speed measurement, the problem is that i´m using a perforate disc with holes, the disc have 4mm of thickness, also the disc will move axially, reason why, the distance between the sensor and the disc, will variate around 10mm, so my question is the next: could be this a problem or not?.
Besides, i´m interested to know which is the minimun diameter of the disc perforations and the separation between this perforations?.
Thanks for the information you could supllies me, waiting for a soon answer
|
A:
The 4mm thickness should be adequate if you are using a steel target disc. The diameter and spacing of the holes will need to be a minimmum of 2 times the diameter of the bias magnet. This is an estimation and may be affected by the strength of the magnet material too. So using a 6mm diameter by 6 to 8 mm long bias magnet you should have 12-14mm diameter holes. The spacing between hole edges should also be equal to the diameter so again about 12mm.
10mm axial variation is going to cause signal problems. The sensor needs to have a steady signal for the peak detecting system to work properly. The 10mm variation might cause too large a modulation of the bias field and reult in unexpected signal loss. 10mm axial variation seems very large. We generally see this device used with airgap variations of less than 1mm. The manner in which magentic sensors of all types function whould cause me say that 10mm axial variation might require some other technology for your application to be successful.
|
Q:
Is the Melexis 90217 Hall-Effect Sensor bi-polar or bi-directional.
I am trying to use this sensor to count the CW & CCW rotations of a motors shaft, low RPM. I see mostly RPM applications on the form and am now wondering if I picked the wrong sensor for the job ? Could I use the 90217 to complete this task ?
|
A:
MLX90217 is a so-called mono-cell sensor i.e. it features only one Hall sensitive element. Consequently, it cannot provide the rotation direction information i.e. CW or CCW.
The sensors capable of doing that feature 2 sensitive elements for which the pitch should be used to build the target wheel (you want to have the pitch equal to one quarter of the full length "tooth-notch" in order to have 2 signals in quadrature and then an easy life w/ the determination of the rotation direction).
In summary, MLX90217 is more for "speed sensing" (RPM, pulse counting) applications.
However, by using a special ("shaped") target wheel as described on Page 5 of the datasheet and taking into account the working principle of MLX90217 i.e. peak detector, it is possible to get the information CW/CCW as a noticeable difference in duty cycle. This can work in practice but it needs of course to be characterized over the application airgap and airgap tolerance, temperature range, magnet tolerance...
You can possibly acheive your goals.
|
Q:
We currently use the MLX90217 sensor for various speed sensing applications where we have a bias magnet at the back.
In one of our customers applications we have the problem that there are sometimes (1 in 1000 pulses or so) erratic pulses. We suppose it could be connected to the internal "intelligence" of the MLX90217 as it is a non standard target (something like a pin). Can you tell me where I can find additional information on the self adjustment mechanisms of the MLX90217? Or do you have another idea what could be the cause of the problem?
|
A:
Sorry for the delay in getting some response to emails or posts. I can not answer this in great detail but the bahavior you observed is not unkown when using the 90217 with a single tooth wheel. There are many factors that could be contributing to the erratic pulses. To really understand the causes woudl require some detailed magnetic analysis of the target and the bias magnet at several airgaps under rotating conditions. Once such an analog map is run it might be possible to comment on the causes of erratic pulses.
|
Q:
Dear Sir or Madam
Pls give a hand in the using about MLX90217.We want to use the chip in the gear velocity measurement.The gear is one module and the teeth distance is 2mm,the distance is 4mm beteen the sensor and the teeth.Can you give some parameter about the magnet and gear.for instance the material of the magnet and the gear,their dimension etc.Special in the magnet paramet.
Look forward for your help.
|
Q:
Pls give a hand in the using about MLX90217.We want to use the chip in the gear velocity measurement.The gear is one module and the teeth distance is 2mm,the distance is 4mm beteen the sensor and the teeth.Can you give some parameter about the magnet and gear.for instance the material of the magnet and the gear,their dimension etc.Special in the magnet paramet.
|
A:
This item has already been discussed on the forum. Please have a look in some previous posted messages about the MLX90217.
To make your life easy, I have inserted it again below.
Any kind of magnet (SmCo, NdFeB, AlNiCo, Ferrite) can be used as long as the amplitude of the magnetic signal modulation (due to the rotation of the wheel i.e. succession of teeth and valleys => AC signal) at the IC level is more than 100 G (10 mT). This should be verified at maximum Airgap (i.e. max. distance between sensor and target wheel). Pay also attention to the magnetic bias itself (i.e. DC component of the magnetic flux density applied on the back side of the IC): it should be maintained below 4000 G (or 400 mT) w/ the proper polarity.
If you take a "cubic" magnet of 5 mm x 5 mm x 5 mm NdFeB and you place directly at the back of the IC, you should be fine.
For the gearwheel, if you take valleys w/ 4 mm depth, you should be fine.
Again, to do a good job, once in the design phase you should measure the field strength between magnet and target with linear hall sensor or gaussmeter and plot this to be sure the signal is adequate for reliable operation over temperature and life.
|
Q:
HI ALL!
CAN MLX90217 BE USED IN CRANK POSITION SENSING (ROTARY ORIENTATION INSENSITIVE)?
|
A:
In principle, the MLX90217 could be used for an active crankshaft position sensor.
It will be able to deliver an electrical signal from the first-edge ("Zero-speed") up to 10000 RPM (i.e. 10 kHz input signal w/ Crank target 60-2 teeth) regardless of the direction.
You will not be able to meet the repeatibility specification required by the engine management control unit and strategy. This is linked to the working principle of the MLX90217 i.e. a fully digital track-and-hold circuitry.
For Crankshaft application, we recommend the MLX90254. This circuit is an AC-coupled differential Hall sensor. It can be used together w/ a back-bias magnet at the front of a ferromagnetic toothwheel. It can also be used at the front of a magnetic wheel.
The AC-coupled differential circuitry allows the MLX90254 to meet extremely tight jitter specification compatible w/ the engine management requirements.
However, it is not a zero-speed sensor.
|
Q:
We are using MLX90217 in one of our speed sensing applications. The input frequency to the chip is 12khz. If the chip is exposed once to high speed sensing applications where input frequency will be 30khz will there be any performance degradation of the sensor once it is brought back to its normal speed sensing range.
Regards
Sujatha
|
A:
The chip will stop functionning correctly between 15 and 20 kHz. At 30 kHz, do not expect a correct function.
However, there is no memory or hysteresis effect in the IC. It means that it will function again correctly once the input frequency is back in the normal range.
In summary, no issue.
|
Q:
Could you tell me why the leads must not arc toward the rear of package?
if i have not enough space to place it & need to arc it,what should i do?
|
A:
I personnally do not see where you get the information that you should not arc the leads toward the rear of the package.
Many people do this lead-forming operation and when it is well done, there is not any risk nor issue.
However, please note that lead-forming needs to respect rules to have no impact on the quality of the parts. Manual lead-forming without appropriate tools (clipping the parts,...) is not recommended for hi-quality mass production. Lead forming of any IC can create latent reliability problems which do not manifest as failures until exposed to thermal cycling and aging effects. Please consult with Melexis Application Engineers for advice on lead forming techniques.
|
Q:
What is the difference between hall chips which has different marking details on its body as below.
1) 17CC
2) 17CA
|
A:
The only diferrence is the number of digital steps for the hysteresis.
Both MLX90217CA and CC fullfill the magnetic hysteresis specification of the product datasheet i.e. 1.8 mT ... 10 mT.
However, the typical hysteresis for the CA is around 4 mT while the CC is around 7 mT.
In other words, you can typically work at bigger airgaps using the Rev. CA. However your capability study for your application needs to be computed with the worst case hysteresis which is idential for both version i.e. 10 mT.
|
Q:
As per the datasheet operating bias magnet for Melexis 90217 can be from 50 to 400mT. What happens if we use Magnet of 1.28 tesla under below conditions. Will the chip give erratic output waveform at larger speed(frequencies upto 12.5khz)?
or the chip will cease completely without giving any output.
The maximum gap allowed from the chip & the ferromagnetic material is 1.27mm. As well magnet & chip are protected in a housing of wall thickness 0.5mm.
|
A:
If you work w/ a back bias of 1.28 Tesla, the chip will not be able to operate as the modulation of the flux density will likely never bring the magnetic signal within specification.
Is there any way in your application to decrease this giant back bias e.g. increase the distance between the IC and the magnet, decrease the strength of the magnet,... It can also give you an economical advantage...
|
Q:
Could you please explain how the chip behavior is if bias magnet strength is 1.28tesla. Will the waveform obtained from it will be erratic at larger speed or it will not give any waveform at all.
The reason behind this question is:
We have used MLX90217LUA in one of our application for gear wheel speed sensing. The speed range is 3906 rpm & air gap between chip & wheel is 1.77mm max. The device marking on the chip is 17CA for first batch. We obtained the required waveform at maximum speed as well.
But now after manufacturing 50 products, the chip output is erratic at larger speed. We noticed the device marking on the chip as 17CC. CC on the device body indicates series & Die rev no. If you replace this chip with 17CA keeping all other items same, waveform appears normal. Other items include magnet & signal condioning PCB etc.
Could you please explain what could be the reason for difference in behavior of two different batch chips.
|
A:
If the Rev. CA is working OK, then the only reason to explain why Rev. CC is not working should be linked to the hysteresis... It means that your application shows a marginal field modulation. Still OK for the typical CA but not good for the typical CC and therefore not good w/ the worst case CA/CC at 10 mT.
Questions
=========
=> Are you sure about your 1.28 T ? How have you measured this ? At the magnet surface or at the operating airgap Magnet/IC ?
=> Have you made a mapping w/ a Gaussmeter to evaluate the modulation while the ferromagnetic target is running... What value do you have there at maximum airgap ?
|
Q:
We are finally arrived at the fact that magnet used by us has the surface gauss strength of 390mT. 12800G is actually the Br Value. Hence we could say that bias magnet used in our application is meeting the 50 to 400mT requirements as per 90217 data sheet.
Now please let me know how the chip behaves when it is affected by ESD. Will it cease functioning completely or still continue to work but there will be performance degration.
Please send us 5 new samples of MLX90217LUA Hall sensors to us in order to investigate cause of failure.
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A:
It is difficult to predict what an ESD damage will cause. First of all, it depends on the pin which is damaged and how it is damaged. We have already seen all the combinations from degradation to non function at all. If you believe your parts have been ESD damaged, please send one or 2 parts back to Melexis for failure analysis.
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Q:
We received the samples & tested for its functionality. But the problem is still persists. The output reading obtained is erratic after 3500RPM. Bias magnet used is having surface gauss strength of 390mT, which is well within the requirements as per the MLX90217 datasheet.
Kindly let us know what exact changes has been made in 17CC with respect to 17CA. This will enable us to resolve the issue as early as possible.
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Q:
Will it be possible for Melexis to supply MLX90217LUA Hall sensors with device marking 17CA in quantities of 100/200nos. per two month.
If so please let us know the availability of these MLX90217LUA Hall sensors in order to enable us to purchase it immediately.
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A:
Let me answer both message together.
Rev. CC has typically a higher hysteresis than the Rev. CA. But, it is again important to notice that Rev. CC and CA has the same maximum spec for the hysteresis at 10 mT.
If it works fine w/ Rev. CA and not w/ Rev. CC, it means that the magnetic flux modulation you have is around 5 mT... which is smaller than the maximum allowable hysteresis. In other words, your system will not work w/ worst case parts from neither Rev. CA nor CC !...
Pay really attention to that as it is not because typical samples are working fine that it will always work fine especially w/ worst case samples.
I again really recommend to make a mapping of your system or a FEM simulation to really check the magnetic modulation at the maximum airgap, minimum back bias magnetic,...
I will request the 200 samples of Rev. CA to our sales department. Please provide your email address and phone number to sales (<sales_europe@melexis.com>).
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Q:
In the MLX90217 product description it is mentioned there are no rotary orientation concerns. Can you specify this in more detail, i.e. what is the (small) influence of the rotary position with respect to a pole wheel. As far as I understood the Hall effect, there will be always be some kind rotary influence unless it is not compensated.
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Q:
You are referring to the comment of the datasheet that "the 90217 uses a single Hall plate which is immune to rotary alignment problems". This has to be understood in the following way:
In fact, as the 90217 has only one single Hall plate it is insensitive to the rotary orientation as long as the Hall plate is perpendicular to the magnetic field.
To clarify even more the sense of this comment, assume that the magnetic field is applied along the Z-axis. Therefore, in order to be perpendicular to the magnetic field, the Hall plate should be located in the X-Y-plane. However in this plane, the orientation is not important.
And even if the Hall plate would not be exactly perpendicalur to the Z-axis (i.e. not be located only the X-Y-plane), due to the fact, that only one Hall plate is used, this miss-allingment will have less impact as it would be the case if two Hall plates would be present in the IC.
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Q:
Working with the 90217 as a rotation sensor for volumetric sensing in
conjunction with a peristaltic pump that presents a rectangular slot/tab
drive mechanism providing flux modulation. The tab width is 3.0 mm.
Rotation rates are low (600 RPM max).
The bias magnet used is 4.76 mm dia with approximately 600mT at the
surface (data provided by manufacturer). The sensing distance is
adjustable from 0.2mm to 1.5mm.
We find the best performance is found for the larger sensing distances
and we achieve reasonable results *most* of the time. However, when
operating for longer durations (hundreds of seconds) we begin to observe
a phenomenon in which the pulse width (low) begins to occasionally
collapse to a very short pulse of only a few microseconds. At first, only a
few pulses collapse, then more and more as time continues. If the
rotation is stopped and the device is allowed to "rest" we get nominal
performance.
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A:
If I read you correctly, the target you are trying to sense is a small tab of 3 mm width linked to a rotating shaft. What is the width of the so-called valley and what is its depth ?
It would be good if you could provide the mechanical profile of your target w/ all the dimensions. The phenomenon you describe is of course strange and is likely linked to how and in what range the magnetic flux density is modulated. It can be either linked to the magnet or the target. It would be good if you could map this w/ a gaussmeter placed nearly at the same position of the IC and the target rotating (measurement step of 5 or 10 degrees).
If you work in the improper conditions, everything can happen such as some marginal effects over temperature,... That is may be what you see w/ the fact that the part operate first OK then start losing its function...
PS: Have you check the polarity of your magnet ? At what supply voltage do you work?
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Q:
We have an idea to use mlx90224 in our speed sensor. Pls clarify the op.temperature which is given as
-40 to 85 c at one point and as -40 to 125 c as one spec.
Also pls suggest the general design points (v low, v high ,pullup resistor value selection )to be considered if a hall sensor should be used as open collector type output.
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A:
The electrical and magnetic specification are measured by Melexis (100%) and guaranteed up to 85 Deg.C. The part does not stop functionning at 85 Deg.C. but the performance can be lower. The parts will operate up to 150 Deg.C. (Tambient = Ta) as long as the junction temperature is kept lower than 165-170 Deg.C. The on-chip power dissipation needs to be considered carefully and should be limited to 100 mW at Ta = 150 Deg.C.
There is no reference to 125 Deg.C. in the specification. Where have you seen this ?
For the application diagram, we suggest 5k pull up at 5 Volt (i.e. 1 mA load current). Do not forget an EMI capacitor on the output (Out) and supply voltage (Vdd). The values for those capacitors depend on the PCB (Printed Circuit Board) design. The value mentioned in the datasheet on Page 6 are on the low side. You may better start w/ bigger value as long as the rise time on the output is not jeopardized (you can still lower the pull up resistor).
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Q:
Thank you for your assistance!
I agree ,there is no reference of 125*C(we mistyped as 125 instead of 150*c).
The temp. specifed at the ordering information,electrical specifications(-40 to 85*c) is different from that specified at maximum ratings
Ta.(-40 to 150*c) So the max.guaranteed op.tmp is 85 or 150 *c?Pls clarify our doubt...
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A:
=1= Maximum rating means you can operate the part up to Ta = 150 Deg.C. as long as the junction temperature Tj stays below 170 Deg.C. The parts will operate correctly but the specification will be slightly degraded.
=2= Specified temperature -40 ... 85 Deg.C. is the temperature range for which we guarantee the specified items e.g. te switching thresholds (Bop, Brp,...).
What is your application and temperature requirement ?
Note: Melexis is working on a redesign of the part to be able to guarantee the specification up to 150 Deg.C. but this part has not been released yet.
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Q:
Suppose I have an ambient temp of 140 degrees Celcius and the current is 5 mA typ @ 5 V, an additional 25 mW is dissipated. What is the thermal resistance of the MLX90224 package, so that I can calculate the junction temp?
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A:
The thermal resistance of the VA package (the one used for the MLX90224) is 200K/W.
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Q:
Does Melexis have equivalent or other hall sensor which operates on 3V supply and consumes less than 1mA current. The application is battery operated hence need low power device?
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A:
Melexis does not have any analog output Hall sensors with less than 1ma current consumption in contiuous duty. It might be possible to use a timer and circuit or a microprocessor control pin to sample the output and reduce the effectibe power consumption but in all cases when turned on the device will draw more than 1ma.
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Q:
I am using MLX90242LUA-CC03 linear hall effect sensor.
I have an application where I have a magnet and the hall effect sensor operating at 128C.
I wanted to know how I would do the temperature compensation calculation for the Magnet and the MLX90242LUA-CC03 hall effect sensor.
The data sheet of the magnet shows that its field strength depreciates at .035%/C above 25C.
Thx
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A:
The 90242 does not have any user adjustable provision for temperature compensation of the magnetic material. The described temperature behavior indicates a Rare Earth Samarium Cobalt material is being applied. Is that correct? The Magnet is losing 3.5% of it field strength at the elevated temperature (128-25=103). This IC has a range for its' thermal coefficent of sensitivity and also for the drift of the null or Voq value. Both will influence the overall Vout drift due to the temperature change. But both have a statistical distribution within the typical range provided in the datasheet. It becomes quite limited to be able predict what any 1 IC will do without specifically characterizing that device over temperature and with a stable magnetic field (from an Helmholtz coil not a permanent magnet).
Meanwhile the MLX90215 or the MLX90251 are available as programmable Linear Hall IC's with the significant advantage that the temperature coefficient can be set to compensate for the loss in magnetic strength by increasing the gain of sensitivity an opposite amount.
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Q:
Is MLX90242LUA RoHS compliant?
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Q:
Yes the MLX90242 is available RoHS compliant. Please contact your Sales rep or distributor for more details and to place orders. www.melexis.com/contact.aspx
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Q:
What is the standby current for the above mentioned sensor? in the datasheet, it shows 1 mA (max) but in the graph, it shows 2mA at room temp.
So is it 1mA or 2mA??
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A:
the standby current is about 3 microAmp. The peak current is about 1.2 mA. The average current consumption is about 10 microAmp.
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Q:
What is the RoHS status for P/N MLX90248.
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A:
MLX90248 is ROHS compliant.
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Q:
Do you provide SMD package in MLX90251?
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Q:
Another question
Can I program the MLX90277 using the PTC04?
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A:
Reply for both posted messages:
MLX90251 is available in so-called leaded package for thru-hole mounting (Single-in-Line Package - 4 leads - 4-SIP-VA).
Melexis offers the option of performing a trimming and forming of the leads in order to get a device suitable for SMD mounting. The parts are then delivered in pocket tape.
Melexis is currently qualifying the MLX90251 in TSSOP-14 package. Release expected by the end of the year 2005. Engineering samples are available in small quantity. It will be referred as MLX90251-E-GO (Option - 0, 1, 2 or 3) for the temperature range up to 85 Deg.C. and MLX90251-L-GO (Option - 0, 1, 2 or 3) for the temperature range up to 150 Deg.C.
This product is then similar to the MLX90277 but the MLX90251 has only one die while the MLX90277 includes 2 isolated dies in the same package (for redundancy purpose).
Both MLX90251 and MLX90277 can be programmed through the Standard Melexis Programming Unit PTC-04.
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Q:
We have got a PCT04 programmer (unit: 04060009, rev:2.3)and we want to program a MLX90251. In our sensors we use two MLX90251. The problem is the following:
We made a cable to the programmer and we tried to program the Hall cells (we tried with two sensor). While we tried to programm the Hall IC, two ICs was ruined. In the first sensor’s dead IC is the Hall 1, and in the second sensor’s dead IC is the Hall2.
After that I made a much shorter cable because our helper suggested that. I noticed the following things:
-If I used the output device A pin (application connector pin 4) the programmer was able to read the EEPROM and made measurment.
-If I used the output device B pin (application connector pin 8) the programmer was able to read the EEPROM but unable to made measurment.
-I tried to run the self test of the programmer but it was failed with Test Xram Roughly fail (bin code: 400).
-We saw the voltage level of the Hall IC’s output and supply voltage with oscilloscope when we tried to read the device. The supply voltage maximum was 9V, and the output maximum was 5V.
If you have any suggestion what should I do please write me.
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A:
1) Please let me first explain the purpose of PTC-04 and the uses for different applications / devices
- PTC-04 is a universal programming toolbox to program all current Hall sensors. A daughter board is used to create the link between the programmer and the sensor/application.
Currently we have 2 type of daughterboards : DBhall-01 ( general DB used for 90215 / 90251 / 90277 ...) and the DB-90316 ( only usable for 90316).
The DB can handle single and dual hall sensors. Single device are linked to device A and dual devices are linked to device A + B.
- The MLX90251 is a single linear hall sensor. This means it should be connected to pins of the DB hall marked as device A.
The pins marked with device B are not accessible by the software of 90251. In the user interface you will find a device selector ( device 1...16), but it is a software switch. It allows you to handle more than one device with the software. There are 16 virtual devices available. Every virtual device corresponds to a single die with separate cache for the EEPROM, independent Solver settings and Solver parameters. The hardware switch has to be done externally by a MUX or relay.
- The MLX90277 is a dual programmable hall sensor, which is equal to 2 dies in 1 TSSOP package. They should be connected as device A + device B. The software of 90277 can handle 8 virtual devices in case an external multiplexer is used.
2) in your application you use 2 x 90251, but for us this is 2 x a single hall sensor and therefore handled as device 1 and device 2.
Even if you connect the second 90251 to device B of the DBhall-01, the software will only measure + communicate with the sensor connected to device A. This explains why you think that you can read the EEPROM of the second 90251, but not see any response or changes in the measurements.
If you compare the EEPROM contents of the 2 devices , then you will notices that they are exactly the same, even the unique Melexis ID.
According to me your you have programmed 2 times the same device, but the second time with wrong solver information and therefore the output will not be as expected. The devices are not damaged and can be reprogrammed if there were not locked.
3) The supply voltage level of 90251 can be 0 / 5 / 9V. 5V is the normal operating voltage and used during measurements. 9V is applied during communication. 0V is selected for resetting the device.
4) The error message that you get during the self test of PTC-04 is not critical and is not related to the mentioned issue. The function that has been tested and reported as fault is currently not used. This error message has been noticed before by Melexis but was related to a software bug. Please check that the latest UI and PSF is installed.
5) In case you want to use 2 x 90251 without an external multiplexer or without manually switching the connector, you could use the 90277 software and connect the 2 x 90251 as a dual sensor , connected to device A and Device B. BUT you can only do this if the VDD is separated, this implements that you have 5 or 6 cables and did not use a common VDD.
( the dual sensor is used for redundancy and implements that everything is separated. 2 x Vdd + 2 x Vout + 2 Vss. A common Vss is acceptable, but not a common Vdd)
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Q:
First of all thanks for the fast reaction.
If I tried only with output device A pin (application connector pin 4) to connect the MLX90251 the connection was succesfull and the programmer read out the EEPROM but with a error massage, and it was unable to programm the sensor. The UI said : Device is not recognized. The Software is unable to program the device. Do you have any suggestion what should I do?
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A:
The curreent version of the UI for 90251 can support 2 types: 90251CC and 90251FA. To change the type you have to modify the ini file and restart the program. ( please check the dokumenttion how to change the ini file)
By default the software starts for 90251CC.
Never use software for the MLX90251CC with samples of the MLX90251FA or visa versa. If you program devices with the wrong software you can make them unusable.
That is why you get an error like "Device is not recognized. " when the wrong type is selected.
Best regards
Depoorter JC
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Q:
I'm trying to program an MLX90251 with the PTC-04 board. I need to measure fields around 125mT (sensors type 2). In the programmer interface, i try to perform the liear set-up: position 1 is, for example, 100mT (0V) and position 2 is 150mT (5V). With a RG of 11 and a FG of 900 the system should work, but when I perform the linear set-up I always obtain the error: out of tolerance. Can you explain me how to program a sensor (in that range) without errors? Is there an example pdf in your website?
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A:
The 90251 is a programmable linear hall sensor, with the following equation
Vout = B x S + Voq.
According to the 90251 datasheet :
- S , sensitivity range 18<S<90 mV/mT ( 90251 option 2)
- B, Magnetic field 62<B<156 mT
- Voq , -10 <Voq<110% Vdd ( or -110..200 in case of full AGND)
Your example requires:
Vout = (5000mV/(150-100)mT) x B - 10000mV
The S = 100 mV/mT is already at the limit, but a Voq or -10V or -200% is impossible.
The 90251 can not be used for this kind of application.
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Q:
I need to programm a MLX90251 FA sensor using the MPT. In a first step I use the Solver to programm the angle range, the voltage range and the clamps. The filter value is set to 0. I disconnect the sensor from the PTC and do some measurements.
Then I need to change the filter value, for example to 15. Thus I connect the sensor to the PTC again.
My problem is: Do I have to use the Solver again and evaluate the positions again, or is it possible to use the "Program EEprom" switch?
I tried using the "Program EEprom", and this destroyed the sensor.
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A:
You can change the parameters manually, without using the solver again, as long as you follow the procedure correctly:
1) "read EEPROM" : The EEPROM contents of the MLX device will be displayed in the grey cells.
2) "Copy EEPROM -> RAM" : copies the contents of the grey cells (EEPROM) to the white cells (RAM). The grey and white cells are registers of the software. The copy is performed on software level.
3) Change values in white cells. You can check the influence of the changes with “Measure by RAM”. EEPROM of device is still unchanged.
4) "Program EEPROM": The contents of white cells are programmed into the EEPROM.
5) “Verify”: EEPROM of device is compared with the target values (white cells)
If you skip step 1+2, than the default values in the white cells are programmed and will corrupt the device.
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Q:
Thank you for your advice. I followed your procedure and everything works fine.
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Q:
My question regards the device MLX90251.
I use the programmer PTC-03 and the device 90251LVA-2 wich I received through your sales representative in Sweden.
Recently I received a device called 90251LVA-3(LF) and my PTC-03 does not recognize this. Can you tell me what the difference between these devices is, besides the sensitivity range (-3), and why the PTC-03 can't connect to it.
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A:
The LF stands for lead free and you will see on the package the description 251F. (The previous description was 251CC.) To program the new version you need an update of the PTC-03 software. Please check with your sales representative for more information. The updated datasheet is available on our web site.
rg
Depoorter JC
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Q:
I have samples of MLX90251 which I would like to test in our application. I wonder if the component works with factory defaults or if it is mandatory to "activate" the cell by programming the EEPROM inside. In this case where can I find the programming protocol.
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A:
You must program the device with the PTC-04. You need to "activate" the device by programming it. You should contact your local sales rep to ask what options might be available.
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Q:
I understand that you must initialise the chip using the PTC-04 but I would like to buy the device only if I'm sure that the MLX-90251-0 is the right product for us. And to know that I need to make a test ! Does anyone know if we can emulate the PTC-04 or what is the communication protocol.
Alternatively, is it possible to have/buy 10 pre-programmed samples, even if all the settings are not optimized with respect to our application I can validate it this way.
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Q:
there is no emulator available.
However, it is possible to order pre-programmed parts via your local sales rep.
In order to be able to pre-programm the parts, please provide us as much as possible information about your application (like Voq level [output voltage level at 0 Gauss], Sensitivity, Clamping levels, Filtering).
Please check with your local sales rep how you would be able to acquire such parts.
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Q:
Hello,
I'm now using the PTC04 to program sensors MLX90251.
The dauter-board is PTC04-DB-HALL01. I cabled as follow:
1. VDD_DIE_1 connected to VDD of the sensor
2. GND_DIE_1 connected to GND of sensor
3. OUT_DIE_1 connected to Vout of sensor
There is no any other component connected to the sensor.
I'm using the connection USB between PC and mainboard.
I installed the MLX90251 UI. Actually, I can read Vdd, Idd and Vout RAM by using Measuring by RAM.
The voltage applied onto Vdd of the sensor is correctly set to 9V when passing in mode program.
However, when I begin with the first step: Read Device + Set TC, there is an error:
The device is not regconized.
Could you please tell me how to solve this problem.
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A:
Hello
The user interface of the MLX 90251 is equipped to handle the MLX 90251CC and FA.The MLX 90251 CC and FA have different read back protocols. If you want to use the MLX90251CC read back protocol, you have to select the type of device you want to use. The selection is made in the INI-file. See documantation of UI how to change the ini file.
Check the description on the package to find out which version you got. FYI : The 90251F is the leadfree version.
rg
Depoorter JC
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Q:
Thank you for your reply.
I checked your sensors. These are MLX90251F so the problem maybe doesn't come from the ini-files. May I not use the logfile?
I wonder if the Readback is not done completely. I mean that maybe the CRC, parity or TC-Table is not correct.
I'm now using the default settings for the MLX90251 UI but I can't pass through the first step of Solver (Read Device + Set TC).
Do you think that I have to change these settings?
Did I cable correctly the sensor to the daughter-board? To where will I connect the pin Test of the sensor?
Thank you and best regards.
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A:
Hello
If you have 90251F, then you should also check if the ini file is correctly set. You should also verify that the description on top of the window is "User interface 90251FA".
The error message is related with the wrong chipt type, not with crc...
Since you can already read the EEPROM, the connections are OK. The test pin is not needed, only Vdd/GND/Out. Test pin should be connected to GND.
rg
Depoorter JC
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Q:
I need the MLX90251 software manual for the PTC-03 programmer. Is it still available on this site or how can I get it?
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A:
The manual can be found on our other site for software and firmware relating to products and programmers at http://softdist.melexis.com/custassetsj
You will require a login and password to be assigned by an admin. Contact your local sales rep to arrange for this login and password.
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Q:
I'm using a PTC-03 with firmware revision 1.64 and UI software revision 1.3 to program MLX90251FA hall-effect sensors. Somehow, it appears that I've programmed one sensor with invalid memory contents (oops...I suppose that's what I get for setting fields manually rather than using the solver). Immediately after programming the device, the output went to the programmed low error output (0.01V measured through the PTC-03). Attempting to read the EEPROM fails with a "The device is not recognized" message, however, the EEPROM Analyzer window shows data and a big red "Parity Failed" message.
Is there any way to bypass the parity check in order to reprogram the device with proper, valid contents? I had something similar happen a year ago on some -CC revision parts and, IIRC, there was a way to force the programmer to ignore the parity and reprogram the device.
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Q:
There is no otpion to disable the Parity check. The fact, that the sensor is not recognized anymore indicates that some bits, which normally allow to indentify the chip, have been changed due to a wrong programming. The best would be not to use this chip anymore, as some trimming parameters (which are trimmed by Melexis) could also have been changed during the bad programming.
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Q:
I am using 2 MLX90254 within 10mm of each other, both with magnets biased with south pole facing the unbranded side of the sensor. I will get inverting output signals sometimes with one or both sensors. The datasheet does not explain this. Can someone?
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A:
We need more details about your application in order to answer you.
- What is the pitch of the target wheel and the tooth-valley ?
- What is the magnetic induction at the sensor position ?
- What is the Delta B ?
|
Q:
I would like to know what is the output voltage of the OUT1, OUT2 pins, which is drive the BLDC motor. This information is not stated in the MLX90283 data sheet.
As far as I have seen, the required voltage to drive a BLDC motor is 1.3V.
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A:
Main application of the MLX90283 is BLDC vibration motors (like in mobile phone) where the nominal supply voltage is 3V.
The voltage range of the device is specified from 1.8 to 3.6V which fits perfectly this requirements.
The MLX90283 provides to the output a typical square signal to drive a single-coil BLDC motor design.
The resulting voltage accross the BLDC motor can be simply estimated and depends on the H-Bridge output resistance RDSon and the output current.
ex: Output current Iout = 100mA
Output resistance RDSon = 2.3ohms (typ at Tj=25degC)
VDD = 3V
--> Voltage accross the BLDC motor:
VDD - RDSon*Iout = 3 - (2.3*0.1) = 2.77V
The voltage accross the BLDC motor is quite more than 1.3V, so you will be able to drive your motor with enough power.
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Q:
If I understood correctly, then one of the OUT pins holds high potential and the other low potential to drive a BLDC motor.
That means: For a given BLDC polarity OUT1 for example will be 3V and OUT2 will be 0V, and for the opposite polarity vice versa?
Am I right?
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A:
Your understanding is perfectly correct.
In the datasheet, you can find the information of the "output behavior versus magnetic pole" where is given the output level depending if you apply south or north pole above the package.
|
Q:
I am deciding to use MLX 90316 for rotary angle position sensing.Please explain the programming part in this IC.I saw one of the IC having OTP programming for same application.how it be in MLX IC?
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A:
The MLX90316 features an EEPROM to store the calibration parameters (such as transfer characteristic offset, gain, clamping levels...). The IC can be programmed through the connector i.e. through the supply and output pins. To do so, you need a programming tools (PTC-04) and the necessary software running on a PC under Windows.
To acquire the full equipment, please contact our sales representative.
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Q:
I'm reading the datasheet and I have some question:
- what is the maximum speed of the magnet(and so the shaft)to get valid angle information (in fast or slow mode) when using the MLX90316 in SPI mode?
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A:
The sensors refresh the SPI buffer every 200 us (fast mode) and every 600 us (slow mode).
Since I believe you are interested in high speed requirements, 200 us will be the refresh rate. If you take the fastest timing to read the SPI telegram, it will also take something like 200 us.
Those 200 us need to be considered vs. your rotating speed and target accuracy for the reading.
Let's take the following example:
1200 RPM = rotation speed of the shaft and the magnet attached to it.
This will give a signal at 20 Hz i.e. 50 ms per period. One period corresponding to 360 degrees mechanical, 1 us will be equivalent 0.0072 degree and 200 us to 1.44 degree. If you can live w/ such accuracy specification, then 1200 RPM would be the max. speed.
If you need a better accuracy, then the max. speed will be lower. If you need a higher speed, the accuracy will be lower.
All the previous statements are of course linked to MLX90316.
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Q:
Thanks for your answer. I'm developing an absolute encoder with a resolution of 10 bits (1024 steps or 0.35 degree/step) at least 4000 rpm (6000 would be better)
I think MLX90316 isn't good for this application, with an accuracy of 0.35 degree maximum speed will be 300rpm, is it right?
For my purpose, as you said, a sin/cos sensor(and a cordic algorithm)would be better.Is there an alternative in melexis sensors?
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A:
You are right for the 300 RPM. We are then one order of magnitude off w/ the MLX90316 and it will therefore not be suitable for your application.
For the SIN/COS sensor, we can recommend you the 2SA-10 from the company SENTRON which is since 2 years a 100% subsidiary of Melexis. You can find the datasheet on the website www.sentron.ch and if you need samples, please send a small message to <sales_europe@melexis.com>. Please refer to this post on the forum for appropriate follow up.
Thanks for using Melexis.
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Q:
we are testing your MLx90316 ( soic 8 ) with the PTC04 .
Our objective is to realize a 360 degree rotary sensors with analog ouput .
In our testing we noted that in a very close zone around
359,8 .....360.....0....0,2 degree the ouput signal is not stable ( the value change in a grea manner )
Do you have a solution for this problem .
thank you .
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A:
This is a classic problem at the so-called discontinuity point around 359.99 and 0 Degree.
You can eliminate the "oscillation" effect at the IC level by setting an hysteresis parameter in the dedicated field of the PTC-04 user-interface.
It should solve your issue. Please note that you can move the location of the discontinuity to any value that suit you if you have an application w/ less than 360 degrees stroke. Please also note that for 360 degrees application, we do recommend to use the digital output (either PWM or SPI) instead of the analog output in order to meet tighter accuracy specification (especially over temperature !).
|
Q:
We've seen on the MLX90316 datasheet the parameter called FHYST (hysteresis filter).
Could you suggest us how to program and use this parameter (on the datasheet - page 15 - we can see only a table without detailed informations)?
Our target is to realize a 360 ° potentiometer without discontinuity point.
Finally, could you please better explain the following: "Please note that you can move the location of the discontinuity to any value that suit you if you have an application w/ less than 360 degrees stroke".
|
Q:
First of all, sorry for the delay in answering.
If you want to do an analog potentiometer application 0 ... 360 Degrees w/o discontinuity, it is basically impossible... Indeed, 359.9 Deg. will correspond to a high output level (e.g. 90%Vdd or 4.5V @ Vdd = 5V) and 360 = 0 Deg. will correspond to a low output level (e.g. 10%Vdd or 0.5 V @ Vdd = 5V). It means that at that stage, you cannot avoid a discontinuity in the output voltage...
However, this discontinuity can be set wherever you want in your application. It means that the actual angle where this happens can be at 50 Degrees or 100 Degrees... The IC allow basically the end-user to define the "0 Degree Reference". The parameter is called "Discontinuity Point" (internal name = EE_DP) and it can be set using the UserInterface of PTC-04.
Let me go back to the discontinuity and the oscillations you are facing around that position. As mentioned above, you cannot avoid the discontinuity i.e. you cannot avoid the transition 90%Vdd => 10%Vdd in the space of 0.1 Deg. (359.9 Deg. => 360.0 Deg. = 0 Deg.). The spring is large in voltage but extremely small in angle. The oscillation or unstability you have seen are directly linked to the noise or jitter which affects the angular reading. In case of +/- 0.1 or +/- 0.2 Deg. jitter around 0 Deg, the angle will vary between 359.8 and 0.2 Deg. through the noise... The output voltage will then vary between 4.5V and 0.5V... If you want to reduce (but not completely eliminate) this phenomenon, you can increase the filtering of the signal. This can be done by using:
(i) strong filter settings (Filter = 5)
(ii) the hysteresis filter (FHyst = X where X corresponds to 0.04 Deg. * X)
In a next version of the chip (Rev. C), Melexis has implemented a dedicated hysteresis at the discontinuity point. This is the most appropriate solution to eliminate the oscillation issue as the discontinuity point.
But w/ the current chip revision (Rev. B), it is also possible to eliminate the issue by implementing a kind of hysteresis (labeled "X" in the formula below -- X = 0.1 Deg. should be enough but you need to consider this with respect to the noise) using the full manual calibration offered by the IC and the User Interface running on PTC-04. You need to set the parameters directly in the EEPROM using the button "EEPROM" (Please use the latest User Interface i.e. Rev. 1.07).
The settings are:
-1- Set DP where you want
-2- Set A = (AX, AY) = (0 , 0%Vdd)
-3- Set S0 = 0
-4- Set SA = 0
-5- Set B = (BX, BY) = (0 + X Deg. , 10%Vdd)
Set SB = (360 - 2 * X)/80 if you want 80%Vdd (i.e. 10%Vdd => 90%Vdd) span for 360 Deg. stroke
-6- Set C = (CX, CY) = (360 - X Deg. , 100%Vdd)
-7- Set SC = 0
-8- Set ClampLow = 10%Vdd
-9- Set ClampHigh = 90%Vdd
This should fullfill your requirement. Other people are doing this in production process and it works just fine. In case of trouble, please recontact us on the Forum and we will address it quicker than this time.
|
Q:
Our objective is to realize a 90 degree rotary sensors with analog output for our pneumatic actuators of butterfly valves with a resolution 0.1°. what’s the position of the magnet and the specific of magnet and program in order to have a resolution 0.1°? ( a magnet with several poles?), and What’s the minimum variation of the magnetic field intensity can be detected by the sensor?
|
A:
The 90316 has a 12 bit angular resolution ( = 360 < 0.1 °). It is recommended to use a diametrical magnetized magnet (min 6mm)located in the center of your shaft and mount the IC into the application facing the magnet.
The package information ( section 19 in datahseet) will give more details of the exact location.
The magnetic specifications are :
- Magnetic Flux density= 20..70mT
- Magnet TC = -2400 .. 0 ppm//C.
Best regards
Depoorter JC
|
Q:
I have another question: What's the difference between the single die and the dual die? We have a better accuracy with the dual die?
|
A:
90316DC is a single die in SO package.
90316GO are 2 dies in 1 TSSOP package.
The 2 dies are independent and electrical isolated ( min 4 M ohm). This package is used in applications were redundancy check is required. Since they are independent and measure the same angle position of the magnet, they can have the same or different output behaviors. There is no improvement regarding accuracy.
|
Q:
I'm comparing the specification of 90316 with other products. but I can't find some specificatin in the datasheet.
How are the sensitivity temperature drift (%/°C), the offset voltage (mV), the offset voltage temperature drift (mV/°C) and the hysteresis error? thank you!
|
A:
MLX90316 is an angular position sensor. All the errors referred to the output are then expressed in Degree. The following table summarizes the situation:
-1- Error at room temperature
==> Initial offset (on sine & cosine signals): +/- 0.32 Deg
==> Sensitivity mismatch (between sine & cosine): +/- 0.3 Deg
==> Orthogonality error (between sine & cosine): +/- 0.1 Deg
==> Non linearity of the raw signals (i.e. sine & cosine): +/- 0.1 Deg
TOTAL LINEARITY ERROR @ 25 Deg.C.: +/- 0.82 Deg
-2- Thermal Error
==> Thermal offset drift (on sine & cosine signals): +/- 0.32 Deg
==> Thermal Sensitivity drift mismatch (between sine & cosine): +/- 0.1 Deg
==> Orthogonality error (between sine & cosine): not measurable
==> Non linearity of the raw signals (i.e. sine & cosine): not measurable
TOTAL THERMAL DRIFT OF LINEARITY ERROR: +/- 0.42 Deg
-3- Hysteresis: not measurable
Note: This information will be part of an application note which will be released soon on the website.
|
Q:
I test a MLX90316 (EVB90316-Rev001)for accuracy. The MLX90316 is preprogrammed from our distributor (as-electronic) with the following parameters.
-CCW
-Analog
-Filter 3
-Slow Mode
-Clamping 10%/90%
-Output 0°-360°
-Reset on Fault
Now my question. If i test the analog output with a reference device. i recognize between 0-approx. 3° (ref. device)the same voltage at the output from the MLX.
But from approx. 3° the output voltage decrease correctly. What can it be?
The original magnet ist centered with the ring on the pcb and had a distance from 3,8mm
|
A:
- From your explanation I understand that with the original magnet the results are OK, but with your reference device the signal is clamped at 90% for 3 deg.
- The sensor can have a linearity error of +/- 1 deg, and maybe you have added an off axes error by not placing the magnet in the center of the device. NOTE That the center of the package is not the center of the rotating magnet axes. See datasheet for more information.
|
Q:
we consider using two MLX90316 on one PCB.
In the data sheet answers to the following questions could not be found:
a) How many MLC90316-GO can share one single SPI bus?
b) In the data sheet in figure „MLX90316 Dual Die – Serial Protocol Mode“ two SCLK lines are used. Why not share one single line?
c)In mass production the two MLX90316-GO must be programmed four times using PTC_04, which is very time-consuming. Can all of them be programmed in one step without needing to reconnect the programming connector?
If not:
Is there a possiblity that the master can programm the parameters via SPI?
d) The MLX90316 is a complex device. Can you provide numbers for failure rates?
e) The range for the allowed magnetic field is very small. Do you recommend to use the SPI mode for getting control over the optimal magnetic field intensity? In analog mode there is no warning if magnets are defective, there is only the feedback via the “diagnostic output level” MLX90316 “OK” or “fail”.
|
A:
a) You can connect multiple 90316’s on the same SPI bus. The number will depend on the capacitor on MISO/MOSI and the frequency on SCLK! 4 x 90316 sharing the same SPI bus is feasible.
b) It is indeed possible to share the same SCLK line for the dual slave application diagram.
c) Programming multiple 90316 with one PTC-04 is done in a sequential way. It is not possible to program them in one step. Also be aware that during the programming with the PTC-04, the Vdd is set to 7.5V. Programming the 90316 with the SPI master is not yet possible.
However we can provide you with pre-programmed 90316 in SPI mode ( 360 deg / high speed).
d) Single die :
-FIT rate = 3.54 - 60% CL
-FIT rate = 7.58 - 90% CL
e) The allowed magnetic field range = 20-70mT. You can not use the SPI mode to get control of the optimal magnetic field strength.
If the magnetic field is too strong or too weak you will receive an error code in case you work in SPI mode, and a diagnostic output level in case you selected the analog output mode.
|
Q:
I have a PTC04 and some MLX90316 for a transducer level indicator. I have calibrated the MLX90316 with the programmer (PTC04) and I have setted SPI as output because I need to reed the values though a microcontroller. With the programmer the device works.
When I try to read the values through a Microcontroller (SPI interface) I see that I have sent 0xAA followed by 9 0xff bytes (pag 23m of the datasheet). After I clock the device to reed the values (10 bytes) but the MLX90316 do not response. I don't know if I wrong something.
What are the programmers steps (for SPI interface)?
What is the configuration to control the device through SPI?
Do you have some library (c language) for microcontroller?
|
A:
Since you mentioned that the device worked with the programmer in SPI, I assume that the device is programmed correctly for SPI.
To communicate in SPI mode with the 90316, it is very important to send the correct command and respect the protocol / timing.
- Send xAAh
When you enabled the SS and send AAh & FFh, then the 90316 will respond with 2 data bytes and 2 inverted bytes. If you send any other value, then the chip will not respond. Please notice that the 90316 should receive AAh , so in case you use the transistor the data is inverted and the microcontroller should send x55h.
- protocol / timing
The timing is very critical and the minimum timings mentioned in the datasheet should be respected. The best way to verify the communication is to look at the signals on a scope and verify with the communication from the programmer.
|
Q:
I have done the steps but the device don't works.
The lines connected from the PTC04 and MLX90316 are VCC, GND e MOSI/MISO. In the 25 pole connector of the PTC04L, VCC is connected with the 1st
pin, MOSI/MISO with the 2nd and GND to the 4th.
With the programmer I do this steps:
- New Device
- "Output Mode" = SPI
- Click on "Set Settings"
- Set of "Angle point A"
- Set the value and click on "Search RG"
- Set the value and click on "Level point A"
- Set the value and click on "Level Point B"
- Click on "Finish program cycle (program)"
- Click on "EEPROM" and I see that the eeprom is programmed correctly
I have seen (in SPI mode), when PTC04 asks the angle values, that the VDD is about 7.5 V and it respond always on the MOSI/MISO line,
the CLK line don't clock the data. The PTC04 uses VCC GND and MOSI to program che 90316 and the response is on MOSI/MISO line.
After I disconnect the programmer and connect the 90316 with my controller (VDD = 5V).
I send, on MOSI/MISO pin, AAh and FFh and I put this pin in input (the time is rispected). the MOSI/MISO line always stay at 5 V (it is due to the
1Kohm pull-up) and the 90316 doesn't respond.
I have seen it with my scope.
What's the problem?
Can you give me an email where I can send a schematic of the connection between my controller and 90316?
I need this response because we won't change the hall sensor of my device with 90316 in about 1 month.
|
A:
I think you are confusing the SPI communication protocol and the 90316 programming with the PTC-04, so let me first explain the 2 communication protocols. Maybe you already know this, but it was not so clear from the last reply.
PTC-04
The programming of the 90316 EEPROM is done using the supply and the output node of the 90316. This is called programming trough the connector ( PTC) and it requires only 3 cables as it is typical used for analog / PWM applications. For reading / writing data from / to the EEPROM, the power supply is raised to 7.5V and the output node is used as for the single wire communication protocol.
Based on your explanation you already succeeded in programming the device.
SPI
The Serial Peripheral Interface Bus or SPI bus is a synchronous serial data link standard designed by Motorola that operates in full duplex mode. The SPI protocol of the MLX90316 is a three wires protocol (/SS, SCLK, MOSI-MISO).
If you connect the SCLK ( pin 3 DB25) and /SS ( Pin 5 DB25) to the PTC-04, then you can also get the readings from the 90316 in the measurement screen through the SPI . The 90316 is considered as a slave node. (Requirements: UI 1.11 and DB 90316 rev 2.0)
If you connect the 90316 to your microcontroller ( See datasheet 90316 : pag 26) and respect the timings ( See datasheet 90316 : pag 22), then the 90316 should reply.
Please check that you send AAh & FFh to the 90316 and it is available during the negative going edge of your CLK signal. If you send me a scope plot of the SS, SCLK, MOSI-MISO signals, then I can verify what could be the problem.
90316 programming
The steps that you performed for the programming is correct for a 2 point calibration. If you want to program the 90316 as a 360 deg sensor, then I would replace the “Set the value and click on Level Point B" with a “overwrite default slopes, after point A with a value 100%/360deg = 0.2777 and click Set “
|
Q:
I'm reading the UI_90316 and I have some question(on the UI_90316 - page 15):
(1)Pull up: Select if a pull-up resistor ( 5K6) to Vbat is required.
Pull down: Select if a pull-down resistor ( 10K) to Gnd is required.
I didn't find the Vbat and Gnd's physical position. Can you give me some detailed informations?
(2)PWM freq: Define the PWM frequency. (Disabled for MLX90316BAD)
Did you mean that the PWM function disabled to use?
|
Q:
concerning your post, please find below some comments.
(1) The PTC-04 offers the option to connect (internally of the PTC-04) to the output pin of the MLX90316 a pull-up or a pull-down resistor. Those resistors are implemented on the Daughter Board of the PTC-04 so that you don't need to connect them externally. However, you have only the option to connect a 5k6 pull-up or a 10k pull-down resistor.
If enabled (either Pull-up or pull-down), the pull-up resistors is connected to Vbat_Norm, and the pull-down resistor is connected to Vbat_Low. Both, Vbat_Norm and Vbat_Low, can be defined by changing the corresponding values in the "Settings" menu of the User Interface 90316. Like this you are able to define the pull-up voltage and to simulate a pull-up or pull-down construction.
(Therefore, Vbat is a voltage source of the PTC-04).
(2) This is not the latest status. Apperently, you are working with an older revision of the UI_90316 document. In the new one, this has been corrected. The actual status is of course that you can chose the PWM frequency.
|
Q:
I have another question. I want to use the SPI mode of MLX90316. When I am trying to program the MLX90316 with the PTC04(choose SPI mode),where are the pins /SS and SCLK should be linked? I just see the functional diagram about Analog/PWM application in the Get_Start_With_MLX90316.pdf document.
|
Q:
in order to be able to establish a SPI communication between the PTC-04 and the MLX90316, you need a MLX90316-Daughterboard of revision 2.0 at least. Any older revision is not able to set up a SPI communication.
I would advise that you check the revision of your Daughterboard and if necessary that you order the latest revision.
In order to get the new UI_90316 document, please provide me your e-mail address.
|
Q:
I have some questions when i use the MLX90316.Could someone help me to solve my problems?
1.When i'm trying the Serial Protocol mode of the MLX90316,how to make the
connection between the MISO and MOSI pins on the SPI Master.
2.How long is the time delay exactly when i get the angle data on the fast mode of the Serial Protocol?
|
A:
1) The application diagram depends on the capability of your micro-controller. In the datasheet MLX90316 ( Pag 26) you will find an example of the connection for a micro-controller without open-drain capability and then you can use a BS170JK (or equiv). For a micro-controller with open-drain capability (for instance NEC V850ES series) you do not need the transistor.
2) In fast mode every 200 uSec a new angle value is calculated. The delay between the time that the sample is taken and sent through SPI is therefore 400-600 uSec.
|
Q:
In the datasheet MLX90316(page 24) I saw that
the angle is calculated continously by the
slave every 350us in fast mode. What does it
mean?
And how can you calculate the delay?
Can you give a detailed steps?
|
Q:
In the datasheet MLX90316(page 24) I saw that
the angle is calculated continously by the
slave every 350us in fast mode.What does it
mean?
And how can you calculate the delay?
Can you give a detailed steps?
|
Q:
is it necessary to use MEMLOCK function for the end of programming?
This “lock” of the EEPROM has any influence to normal operating of the sensor?
Thanks
|
A:
The memlock does NOT have any influence on the normal operation in the application.
If the memlock bit is set, then the device is protected against all writing attempts. The customer can decide if this is needed, but for example in automotive applications locking the device is a requirement.
The question is: Do you want to deliver a product to your customer that still has the option that the functionality can be changed?
|
Q:
The datasheet rev.3 of mlx90316 describes a switch out function, it has two parameters,KD and KDHYST, but I don't find them in MLX90316BCG EEPROM parametes, and my qutestion is how to use this function, how to find the parameters.
|
A:
The parameters in the EEPROM are CodeKD & CodeKDHyst. These can be changed with the PSF instruction SetEEParametervalue in degrees or with the latesr 90316BCG UI.
How to use it ? Define the angle position were you want the digital output to switch.
|
Q:
Thank you very much, My MLX90316BCG UI revision is 1.2, how to download the newest revision 90316BCG UI?
|
Q:
what's the difference between the mlx90316 and the new mlx90333. i mean they use the same triaxis technology, right?!
which technology is used for production of these sensors, is it a cmos technology? cmos is mentioned in the data sheet, but which depth?
|
A:
Correct, they use the same triaxis technology.
The technology is monolithic CMOS, 0.35 µ.
The difference between 90333 and 90316 is the firmware / software which run on the microcontroller, and therefore defines the behavior (or application) of the device.
90316 measures Bx & By to calculate one angle = Atan( By/Bx) , while 90333 measures Bx, By & Bz to calculate 2 angles.
|
A:
Latest software ( Copy of CD PTC-04) is available on sotdist.melexis.com
Registration is required. See your local sales rep to register.
|
Q:
Is it http://www.sotdist.melexis.com ?
Our company purchased 1kpcs mlx90316, marked flag is 316BCG P21439/X2 on its surface. I want to know they have the switch function.
|
A:
Hello
- http://sotdist.melexis.com ?
- 90316BCG has indeed the switch option
rg
JC Depoorter
|
A:
I think there is a typo causing confusion here the address was meant to be http://softdist.melexis.com
in previous posts there was missing an "f" in the url. Still a registration is required and this is not obvious how to accomplish when arriving on this page.
You need to request a registration for the software distribution system. You should do this through your local Melexis office or through the sales channel that sold you the PTC-04.
|
Q:
I am working on a project using multiple microcontrollers and multiple MLX90316 devices. The project uses SPI mode communications.
I am starting with a schematic produced by my German colleagues, and I have a question about how they implemented the SPI interface.
I believe that if the SPI interface inside the MLX90316 works like typical SPI devices, then the clock and data signals should be ignored if the slave select line is not active. The schematic I am basing my work on has multiple lines to ground out the clock to idle MLX chips, but I believe that these should not really be needed.
Can you confirm for me whether the operation of the device ignores clock and data lines when the slave select line is inactive?
|
A:
I confirm that if /SS is high, the signals on MOSI and CLK are ignored and the MISO will stay HiZ. That is the purpose of the /SS or chip select.
|
Q:
I've received some analogue samples of the MLX90316 but the output is stuck at 0.4V. Do I need to program them with the PTC04 or am I doing something wrong? How much does the PTC04 cost?
|
A:
If the output is stuck at 0.4V, then you received for example the normal 90316EDC-. For the preprogrammed analog parts you need 90316EDC-PPA.
You can program the 90316EDC- with the PTC-04 and this programming tool costs around 1200 Euro.
|
Q:
Hi, I got samples of 90316 in TSSOP package. They have been send in tube. Do you also offer tape and reel for the TSSOP16 or the SOIC8? Which other delivery froms are possible.
|
A:
We have following delivery forms:
TSSOP16:
Tube: 90pcs
T&R: 4000pcs
SOIC8
Tube: 97pcs
T&R: 2600pcs
If you have further questions, please let us know or ask your local distributor (AS Electronic, Future Electronics or Dacom West). Contact information of our local distributors can be found on our contact page.
|
Q:
What's the performance of the sensor with the Integrated Magneto-Concentrator (IMC) ?
Is it the same that you specified in the Application note (Front-End Calibration of MLX90316 page 8 /8) ?
Do you have some measurements on the performances of MLX90316 with IMC following different magnets such as the Application Note: Magnet selection ?
With an IMC, is it possible to take the same waveform Flux density vs Axial distance (Application Note: Magnet selection figure 6 page 4 /7) ? The idea is to avoid a saturation of the sensor and Non-linearity.
|
A:
We recommend using a diametrical magnetized round magnet, with a minimum diameter of 6mm. The bigger the magnet, the smaller the non-linearity error due to off-axis shift between sensor and rotating magnet. Different magnetic materials can be used ( NdFeB , SmCo, AlNiCo , Ferrite, ..) since the TC of the magnet does not influence the calculated angle. Imperfections of the magnet material will of course result in the angular errors.
|
Q:
i am haveing problems using the SPI interface (to PIC18F1320) of the MLX90316. If your offer of help still stands, i would much appriciate it.
|
A:
if you are still having problems with SPI I am using a 90316 connected to a PIC18F452. A small amount of extra interfacing is required, to bring the voltage levels to acceptable levels.
|
Q:
I have got a question about the distances and dimensions of the magnet.
I would like to know if I can use a magnet almost as big as I want, like a diameter of 12-14 mm, just to decrease the eccentricity-error??
I would also like to know how big a distance I can make between the magnet and the device or is it enough jsut to increase the magneticfield of the magnet, I would like to have about 6 mm between them....??
I have recieved a preprogrammed chip from you and its linear setup is configured as a 360 degrees application. The setup goes directly from 0 to 360 degress with an slope of 0.278, but when i use this configuration in my own setup it won't work, I have to put in a mark at 50 % - 180 degrees, can this be right...??
|
A:
- You can select the magnet almost as big as you want. 12-14 mm is no problem.
However, to choose a magnet as big as possible will not always lead to the best result:
• Large magnets can be less homogeneous then assumed (‘hot spots’ on the magnet surface will create angular errors) Quality can be important
• Big magnets are more expensive
- Big magnets will give strong fields and need a big distance between sensor and magnet; otherwise it will cause saturation effects. If you need a 6 mm airgap, then select a magnet that will have a horizontal magnetic flux intensity of 45-50 mT at 6.35 mm.
Check this with your magnet vendor, since the flux density will depend on your choice of material, diameter and thickness.
- The preprogrammed parts are indeed programmed for a 360 angle span, and have a slope of 80%/360 deg = 0.222 ( in case of analog / PWM) , and in SPI the full output span is used = 100%/360deg = 0.2777.
I think you are referring to the programming points with the solver, and it is possible that you need a mark at 180 deg. With the solver you cannot use 0 and 360 deg as marking points, because the slope is calculated based on the difference ( for the 90316 360 = 0 => 0-0=0) . So either take 0 and a fixed slope, or 0 and 180 deg, or 10 and 350 deg or ….
|
Q:
We require our product to be programmable for either Analogue or PWM mode. However, revision 003 of your data sheet shows a capacitor of 100nF between Output and GND for Analogue mode (Fig. 17.1) and 4.7nF for PWM mode (Fig 17.3). This suggests that a hardware change would be necessary to change between the two modes, which is unacceptable to us.
However, your document ' 0005269_MLX90316_PTC04connection_Rev12_JCD_27Nov06.pdf ' shows an MLX90316 connected to a PTC-04. It is labelled ' Analogue/PWM application ' and shows a 47nF capacitor connected between the Output and GND.
Please confirm whether we can use a single capacitor value for both modes and, if so, what its value should be?
|
A:
In analog mode the 90316 needs a capacitor of minimum 47 nF. In PWM mode it can be as small as 4.7nF and will mainly influence the rise/fall time of the flanks.
If the signal in PWM mode with a 47 nF is acceptable for your application, then you can use this value for both output modes.
|
Q:
I'm wondering if the chip is preprogrammed for at 360 degrees application??
I'm asking because the samples I recieved from my supplier here i Denmark, simply just functioned, I just had to connect it to the daughterboard, and then it just started measuring.
Another question, do you have a protocol for the device, because it's very expensive to manualy program the devices one-by-one. If I had the protocol I could simply use one of the microprocessors in my application to program the device, it would be a lot easier and cheaper for us...??
|
A:
- By defult the 90316 is not programmed for 360 degrees application. The output is in analog mode and clamped to 7..8% and always require a PTC-04 to program the part. You probably received a demo sample that was programmed by Melexis or your local rep.
- Programming the 90316 can only be done with the PTC-04, there is currently no possibility to program the part with a uC. We have to make a redesign first to change this and this is planned for next year.
|
Q:
I can't understand that it isn't possible to program it in any other way. If you just go into communication-mode by raising the supply voltage to 7.5 V and if you then know the protocol it must be possible to write directly to the EEPROM, or maybe I'm wrong....??
I'm very interrested in this, because I should only use 1200 pieces yearly, and it would be very expensive to program the devices one-by-one, and then mount them at a reel again....
|
A:
- In case you use SPI communication we offer preprogrammed devices. In all other cases you will need the PTC-04 to program the parts in the final application trough the output pin.
- There is a company in Germany that can offer a service to program the parts for you.
- We do not support anymore the protocol how to program the parts. From previous projects we know that it will be very time consuming for you and for us to get it work correctly and in the end it will cost more then the PTC-04.
|
Q:
I'm going to use SPI communication, what is the price for the preprogrammed devices, and what specs do they have??
|
A:
The parts are preprogrammed as follows:
- 360° angle
- 10-90% analog output
- 2.4 ms
For pricing and ordering please contact C88, your local distributor in Denmark:
C88 AS
Savsvinget 7
Hoersholm
2970
Denmark
Phone +45 8683 7531
E-mail ba@c88.dk
Web www.c88.dk
|
Q:
Refer to my datasheet of 90316,see the below:
"
Pre-Programmed Analog – 360deg angular span for an analog output between 0.5V and 4.5V, Low Speed Mode (Locked)
"
My question is,
May I have pre-programmed 90316 ,of which is NON-locked? so I can programming it via my PTC-04 later;
And will you charge me more money? :)
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A:
We offer 3 types of pre-programmed locked 90316 and 1 un-programmed/unlocked. If you order the un-programmed, you can program the parts with your preferred settings and keep them unlocked if needed.
It is impossible to deliver customer specific parts, unless there is a minimum production quantity guaranteed.
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Q:
Are the MLX90316 parts that are available from Digikey pre-programmed or not? There is no pre-programmed suffix on the part number. Does Digikey program them? How would I get 3 or 4 of these parts programmed? I am in Canada.
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Q:
I received one Evaluation baord of MLX90316 from Digikey.The Evaluation board data sheet suggest that by default it is programmed in analog mode for (o to 360degree)but i am not getting any response on output pin.Is it preprogrammed and locked in SPI mode? If yes the do you have any application code using which i can read values?Is it possible to program the chips of evaluationm board with PTC-04?
Please suggest soon as i have to make one Prototype using this IC.
Regards
Abhishek
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A:
You may have received a locked SPI board. I will contact by email to replace it. You can't reprogram the device by the SPI interface.
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Q:
I successfully managed to "talk SPI" with the 90316, however it always report a valid angle value, even if there is no magnet on top. Is there a parameter on the 90316 which is programmable with the PCT-04 to enable error reporting in SPI mode?
PS: in SPI mode I have a valid 16bits value and its 1 complement.
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A:
There is a programmable EEPROM parameter called "Resetonfault" and this parameter enables/disables the fault detection. By default this setting is disabled for non programmed parts, and to enable the error detection you need to set the resetonfault =1.
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Q:
It is indeed much better, now I can retrieve the errors, thanks!
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A:
.
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Q:
Everytime I program the devices EEPROM to use SPI I loose the communication with the device and when I try to reprogram it to analogmode, it just comes with an error...
Can this be right...??
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A:
When the 90316 is connected to the PTC-04, there are 4 possible modes:
1) Normal operation mode, analog or PWM output ( Vdd=5V)
2) Programming mode ( Vdd=7.5V)
3) SPI mode ( Vdd=5V)
4) Switched off ( Vdd=0)
Switching between the different modes is in general possible without restrictions, except if the device is in SPI mode.
Once the device is in SPI mode it is required a reset before it can go into programming mode.
To make sure that you can enter into programming mode, reset VDD or hotreset the device twice. In the latest UI ( rev 1.11) this should be fixed.
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Q:
I am starting to work with the MLX90316 part and I have implemented the recommended SPI circuit with the open drain/pull up configuration on the MISO/MOSI lines. I am finding that the MLX90316 side of the circuit is continuously driving the MISO/MOSI line low which does not allow it to wiggle. I remove the part and my circuit properly wiggles both lines. The part is virgin, the test pins are grounded and the Vdig pin is bypassed with a 0.1uF cap.
I’m looking for suggestions on what might be going on. I assume I’m missing a subtlety.
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A:
If you receive virgin 90316 parts from Melexis, then the 90316 is in an analog test mode and the output is clamped to 8%. Vdd.
To use the 90316 in a SPI application, the part needs to be programmed with the PTC-04. If you do not have a PTC-04, you can also order preprogrammed parts for SPI mode.
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Q:
I just bought one of these sensors from Digikey for about 16$. Here is the link to the actual product. http://www.digikey.com/scripts/DkSearch/dksus.dll?Detail?Ref=412607&Row=785717&Site=US
Now I notice that there is some sort of PTC04 programmer for this device.
My question is, can I use the sensor I bought or is it completely useless? Secondly, if I can't use it at all, can Melexis provide me with at least a sample that I can use for my university project? If you could let me know that would be great. Thanks.
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Q:
if the part is not a pre-programmed part, unfortunately, you are not able to use it without the programmer PTC-04. However, it is possible to get pre-programmed parts (pre-programmed by Melexis). Please contact us directly.
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Q:
I want to use the SPI interface of the sensor. Is there something to do to initialize the SPI interface? Thank you for giving me a documentation about how to use the SPI interface.
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A:
The 90333 is a programmable device and the output is configurable for
- Analog output mode ( 5-95 % Vdd) = default
- PWM output ( 0-100 %)
- SPI output ( 0-100%)
The device needs to be configured for SPI with the PTC-04 before the device can be used as a SPI-slave.
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Q:
Do the 90333 using the same daughter board of DB90316 or have a new daughter board for 90333?
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A:
Yes you can use the same daughterboard.
The 90333 is a derivate product of the 90316 (same hardware but a modified ROM/firmware)
Initially the marking on the package was 90316BCH, which is now changed to 90333.
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Q:
I need the '316 with an SPI interface, but all I can find in stock (anywhere) are analog output. Can analog output parts be reprogrammed to use SPI?
Where do I get the programmer?
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A:
The best way to get this information is to contact sales_usa@melexis.com. They should know the details about parts in stock in the US.
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Q:
I’ve got a problem with CharacterizeOutputDAC. The values I receive are wrong. For example, I receive:
Gain=1.027, Offset -2.3, MPT Toolbox reads Gain=1.004, Offset=-0.139. Especially the Offset is obviously wrong.
Previously, my programming routine in VC++ worked fine. Until this week, we used MLX90316-BAD, and now we want to switch to BCG.I now upgraded to the BCG-PSF, I upgraded the PTC-04 to the new firmware and installed new MPT Toolbox and UI module for BAD and BCG.
I also tried setting the chip version (is this necessary?) but the set_ChipVersion routine doesn’t exist in the Advanced object.
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Q:
Well, I found the solution. The function to set the EEPROM Parameters to the correct Chipversion which is called "set_ChipVersion" in the documentation actually is named "put_ChipVersion"... After that, CharacterizeOutputDAC works fine.
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A:
- Setting the correct chipversion is indeed very important, because the software will then use the correct EEPROM locations.
- It depends which builder is used. For example in MS Visual C++ it will be put_ChipVersion, but in Borland C++ - set_ChipVersion.
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Q:
I try to use the FTDI chip FTD232R to simulate the SPI interface to the MLX90316 chip. Unfortnately, the clock pulse with, produced by the FTDI chip is not consistent. One clock pullse is maybe 2 micro seconds, but the next one is 35 micro seconds.
My question is, is the clock critical for the function of the MLX90316 or not?
Can someone help me?
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A:
Only the minimum time is critical. It's OK if it is inconsistent. There's no maximum time. The minimum spec for the clock period is 2.3uS in FAST mode, 6.9uS in SLOW mode. See section 16.8 of the datasheet.
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Q:
One other question concerning this part. Do the parts with EDG product codes ship automatically with SPI enabled and fast mode on by default? This is not clear from the documentation.
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A:
It depends on the option code ( see also order information, pag 1 of datasheet and the default EEPROM values , pag 15)
If you order :
MLX90316 E DC - = analog, clamped output @ 8%Vdd. You need PTC-04 to program the device
MLX90316 E DC - SPI : SPI Version pre-programmed and locked for 360deg rotary position application in SPI mode (High Speed).
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Q:
This is strange -- the parts we have ordered have a E DG code. Is that a newer option? Would the letters "SPI" be indicated on the part itself, or only in the order form? Our parts do not have the letters "SPI" on them.
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A:
These order options exsist already for a long time.
On the pakacge you will only see "90316 BCG" or "90316 BDG", NOT the E / SPI code.
( See also pag 36 of datasheet)
If you have ordered the 90316 EDC-SPI, then the marking on the device will be BDG, otherwise it will be BCG. ( 90316 EDC , 90316EDC-PPA , 90316EDC-PPD)
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Q:
I'm trying the MLX90316 for measuring the angle of a hand made mechnical system, but I've noticed a constant error in output data which is repetitive at every cycle with the same form and magnitude, this made me think that the error is due to mechanical errors and especially eccentricity(centering of the magnet).So if a relation exists between eccentricity and output data please supply me with.
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A:
- The typical non-linearity error of the 90316 is <1 deg and the signature of the error is the sum of a single and double period.
- In case of an eccentricity error between magnet and hall plates, the max non-linearity error is more or less equal to 320 x (offset)^2 / 4D^2. (D = diameter of magnet)
This means that angular errors due to a given off-axis misalignment are becoming smaller with increasing diameter of the magnet. The signature of the error is a double period over 360 degrees.
- If the signature of the error is a quadruple period over 360 degree, than we identify this as a saturation error and is caused by a too strong magnetic field > 70mT.
Based on the shape (number of periods) you can identify the nature of the error.
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Q:
Thanx the information was so helpful, and this was exactly what I need.
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Q:
Does the answer apply equally to the non-redundant and redundant versions of the chip?
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A:
Yes, the answer is applicable for both packages.
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Q:
hmmmm... perhaps the answer is found in your statement that the calculation is based on the offset "to the Hall plates".
Am I correct that there are two Hall plates, and they are not centered at the same spot in the chip package? If true, would there not be a fundamental difference between the two outputs, given some magnet offset?
This is the real question: With a redundant chip, a fundamental requirement is to be able to compare the output of one chip with that of the other for safety purposes. Sometimes this is called interlinearity.
Given a range of radial offsets (both in magnitude and direction), will BOTH outputs respond to the offset in exactly the same way? That is, will the two output signals still track (correlate) with each other, or will you see a greater error or perhaps a difference in the arithmetic sign of the error between the two outputs, depending on the direction of the radial misalignment?
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A:
- You are correct that there are 2 different positions in the redundant version, and they are centered in only 1 axis, and a small difference in the other direction. (See package information in datasheet.
- The redundant version is 2 x the 90316 die in a TSSOP package and this offset difference is compensated during the calibration step in our production. The nonlinearity error for both outputs can be +/- 1 deg over 360 deg, but the interlinearity is then in worst case +/- 2 deg
- In case of an eccentricity error, both outputs will have an error but not necessarily exactly in the same way. The signature of the error is for both a double period over 360 degrees, but the magnitude / 0 deg error crossing on the X axis can be different..
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Q:
"In case of an eccentricity error, both outputs will have an error but not necessarily exactly in the same way."
This is exactly the point of my question, but I am not clear on the answer.
Assume a magnet of 8 mm diameter. Now assume a radial offset between magnet and center point between the two Hall elements of 0.5mm.
Assume that this error can in one of four orientations with respect to the chip, +X, -X, +Y, and -Y. For each of those four conditions, what will the errors due to eccentricity be in outputs 1 and 2?
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Q:
Does the height of the magnet in any way relate to the eccentricity error (assuming optimum spacing between the chip and magnet in all cases)?
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A:
The height of the magnet will influance the magnetic strenght, but not the direction and also not the eccentricity behaviour.
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Q:
I would make an example to right understand the formula on the top:
320 x (offset)^2 / 4D^2. (D = diameter of magnet)
I have eccentricity d=0.5mm and an Magnetdiameter of 10mm so the amplitute of the non-linearity errror is..
320 x (0.5mm)^2 / 4*(10mm)^2 = 0.2%FSR(Full Scale Range)
Is this correct?
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Q:
unfortunately, your interpretation is not 100% correct. In fact, the eccentricity error is not given in %FSR, but directly in degree.
This means that for your example we have:
Error = 320 x (0.5)^2/[4 x (10)^2] = 0.2Deg.
Furthermore, I would like to emphasize to the fact, that this formula only gives an approximation.
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Q:
I have a problem with my PTC-04 updates I have been doing over the last few weeks. I am using the PTC-04 to program the 90316. I now have gone to use the programmer for the first time after doing my updates and I get a conflict of firmware revision, specifically error message 'firmware revision too low, detected 1.36 required 1.45'. The firware I have is the only one I have ever had .. .. .. 'PTC04_mlx90316_firmware.hex'.
When I look for the updates I don not see any revision update to the 90316 firmware.
Any feedback would be appreciated.
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A:
If you update the software on your PC, than it is also required to update the firmware on the PTC-04. This should be available on the same location as you got the software update. Check for FIR0316AAMLX, rev 1.47.
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Q:
Hello,I have the same problem too,so
how can I upgrade for my PTC-04?
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A:
To update the firmware of PTC-04 you can start the user interface of PTC-04 and press the "upload firmware "button. In case you have an older revision of the UI PTC-04, then you can start the firmware commander and use the upload firmware instruction.
For more information, please check the manual of the user interface PTC-04 on the CD.
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Q:
In PTC-04 programmer there is a option "Sensitivity mismatch" and 2 parameters SMISM[8] and SxGTSy[1]. My question is what these parameters do and the limits for first one? I know that this is for amplitude error (sin cos) but I don’t know how to use them in practice? Because in doc there is no info obout.
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A:
The parameters SMISM and SxGTSy are 2 values that are determined during the front-end calibration at Melexis and are defined as calibration parameters (together with the offset and orthogonality) for correcting sensitivity mismatch X/Y. These parameters are inside the Melexis area, and should not be changed for end of shaft applications.
SMISM defines the Sensitivity mismatch correction factor applied on either X or the Y value, correcting the signal in the range 100%..125% . The SxGTSy bit specifies which value is compensated; because correction factors less than 1 are not possible to prevent ADC clippings.
Formula, Case SxGTSy = 0
Cos <= Cos * ( 1 + SMISM / 1024 ) , and Sin <= Sin
Formula, Case SxGTSy = 1
Cos <= Cos, and Sin <= Sin * ( 1 + SMISM / 1024 )
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Q:
Thanks for the answer.
Now I have another question In PTC-04 programmer there is an option „Output DAC“ . Do I need to Characterizie each time when I programming sensor (this is obligatory or not). Because same time this make bigger output faults (linearity error over 360 deg) and other no changes.
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A:
The CHARACTERIZEOUTPUTDAC method calculates coefficients OutputDacGain+ OutputDacOffset for level correction in case of an analog output, and will be used in all calculation of the output level in %Vdd. This method will program and measure the output at 10 % & 90 %Vdd, and calculate the gain + offset.
Since every device has his own Digital to Analog convertor, this function needs to be called for every device at the beginning of the program flow.
This method wiil improve the accuracy and not
increase the error.
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Q:
I've been asking myself , why the MLX90316 is called a TRIaxis Sensor.
To calculate the angle only Bx and By are used. So where's the third flux component ?
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A:
It is indeed correct that the uC of 90316 calculates the angle based on Bx and By, and the Bz component is not used in this application.
If you look at the detailed description in the datasheet on pag 6, then you will notice that the front end sensor is made of conventional planar Hall plates and an IMC. This means that the sensor is capable of measuring the fields Bx, By and Bz , and therefore called a Triaxes front end sensor.
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Q:
I look for datasheet,but don't see the How into programmable mode.
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A:
For prgramming the 90316 you will need the PTC-04. Please check the reference "Link to SW 90316 PTC04" or goto http://www.melexis.com/Asset.aspx?nID=4995
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Q:
I am going to make MLX90316 in SPI mode.I tested with MLX90316 and here output is analog mode.
How can i make it from analog to SPI mode ??
Do i have to configure in Hardware to make it in SPI mode ??
How can i make it slow to fast mode ??(Software & hardware)
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A:
The MLX90316 has to be programmed in SPI mode using the PTC-04 programmer. Same for the high speed mode. If your application is 360 degrees and if you do not need a calibration, you can also order the MLX90316 already preprogrammed in SPI mode. Otherwise you need the PTC-04 programmer.
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Q:
I think i got non-programmable MLX90316 device.In my application, I need only angle measurment (0 to 360) so i think i can order only MLX90316 preprogrammed in SPI mode.
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A:
Yes, if you order MLX90316 E/K/L DC/GO with option code SPI , then you will receive a pre-programmed 90316 device, locked for 360deg rotary position application in SPI mode (High Speed).
Please check the datasheet:Ordering information on pag 1 for more details.
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Q:
Is it possibly to use the PTC04 programmer with a custom cable / adapter to program the MLX90316 on a board.
The PTC04 Connections REV12 diagram : "Functional Diagram SO – 3wires / SPI" suggests it may be possible.
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A:
,
Yes, most customers program the MLX90316 on the PCB. Please see the application note:
http://www.melexis.com/Assets/MLX90316_-_PTC04_connection_diagram_5269.aspx
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Q:
Is there any harm in leaving the programming of the MLX90316 unlocked? We have an application where we may want to change the output curves in the field.
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A:
The chip works perfectly when leaving the programming unlocked as long as you are 100% sure that you don't send wrong programming commands to the chip.
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Q:
I`m going to use integrated circuit MLX90316 (produced by your company) in my
design. I have one question, although the datasheet has been read by me.
1. Especially, I will have to measure high speed rotation up to 20000 rpm. So
that, what resolution per rotate will be achieved for this speed in analog (the
fastest) mode? Is this IC suitable for that hight speed and required resolution
about 6-7bits?
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A:
In high speed mode the typical refresh rate is 200 µSec. For one rotation per minute , this corresponds with 360 deg / min = 6 deg/Sec.
The resolution for 1 rpm is then equal to 6 x 200 µSec = 0.0012 deg.
In case of 20000rpm, this corresponds with 24 deg or 4 bit.
If the required resolution is 6 bit, then the max speed rotation = 4687 rpm.
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Q:
I'm working on a reduction of the resulting eccentricity error.With the enlargment of the magnet diameter could the error minimized. Does this enlargment have some limits? Is the reason of the errormelioration a better homogeneous magnetfield?
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Q:
Indeed, there are some limits.
1. You should make sure that the magnetic field strengh will not go out of the recommended range (20mT - 70mT).
2. If the diameter of the magnet is increased, the risk to have "hot spots" is also increased, i.e. the magnetic field will not be homogeneous anymore over the whole magnet surface. Therefore, it is recommended to have the diameter as small as possible and as big as needed.
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Q:
Dear Sirs, I received few MLX90316 samples few months ago. They are marked as 316BAD X1. I wired it as it is in analog mode and I measured on the output pin 0.4V. According to one of your previous posts on the forum I assumed that device is in analog mode. But, after I applied magnetic field above device I didn’t measure any change on the output pin. Is it possible to determine in which mode is device without using PTC-04.
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A:
You have received parts with the default programming from the Melexis final test, what we called also un-programmed part. Clamping High and Clapmping are programmed in such a way the output is around 8 %Vdd, which is 0.4 V. The mode is analog. This allows to test the PCB without programming. You need a PTC-04 programmer to change the programming. Also, you can order pre-programmed part in analog mode, but on 360 degrees from 0.5V to 4.5V. See page 1 of the datasheet Rev003 available on the Melexis web site.
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Q:
I have a question about the solderability of the TSSOP16 and SOIC8 package. What is the MSL level of these packages?
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A:
The 90316 package is qualified as MSL3.
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Q:
I'm using MLX90316 as position sensor.
How could I get clockwise parameter of output transfer characteristic from the chip.
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A:
There is a parameter in the EEPROM that defines the polarity of the rotation. By default the 90316 is set to counterclockwise, which means that turning the magnet Counterclock-wise will cause the output voltage to go up. To switch to clockwise, select clockwise in the user interface/EEPROM or set the parameter ( codeRotationDirection =1) in case you use the PSF library.
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Q:
I’m a Norwegian engineer testing out your MLX90316 for use in a wind direction sensor application. Is it possible to program the device without the PTC-04? It seems like “overkill” for me to purchase the PTC-04 just to be able to test the MLX90316 to see if it’s useful for our application. I want to use it as a 360 degree sensor with analog output. What’s the device default state/configuration?
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A:
You need a PTC-04 to program the parts according to your specification.
For 360 Degrees application, we offer for big quantities (> 250k) preprogrammed parts feat. the SPI protocol.
However, for your evaluation, you can order few samples to sales_europe@melexis.com preprogrammed for 0 ... 360 Deg. and 10%Vdd ... 90%Vdd analog output.
We look forward to your order.
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Q:
Hello,I am working on one test solution of 90316-relevant product;my questions:
1) Memlock Command must follow the program session or just independent?i.e. I want to memlock my 90316 only if it is tested OK;2)if I want to apply PTC-04 as programmer in Mass Production, how to maintain it in health condition?(it is the most expensive in my solution)
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A:
1) The memlock function can be executed independently of the programming, but should be done after programming the MLX90316. Locking the device is a final operation and the EEPROM becomes un-programmable.
2) Every time the software is started, the software performs some checks like checking calibration date, firmware revision...
The user interface of PTC-04 has a test program that is made to perform a quick check of the hardware. It allows the user to verify if there is any hardware damage on his PTC-04 programmer. The test checks the functionality of the fixed power supplies, programmable power supplies, the internal voltmeter, etc…
To start, press the button “Test programmer” on the PTC-04 User Interface.
We also recommend performing a calibration of the PTC-04 every year.
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Q:
I have a sample MLX90316-KDC chip hooked up to a PTC-04 using the SPI method mentioned in the PTC04 Connection PDF.
When trying to program the chip I get errors saying that I can not write to the specified address. Also, when reading the EEPROM, I see that the checkbox for the "MLXLOCK" is checked. Is this the sign of a chip that has been preprogrammed and locked from the manufacturer?
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A:
Yes, this means that the device has been locked and you can't program it. Did you order the MLX90316KDC-SPI? These parts are locked by Melexis.
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Q:
I ordered part# MLX90316KDC with no suffix. Is it possible to tell what sensors I actually received with the PTC-04?
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A:
It looks like you have received -SPI samples. Customer service will assist you to replace them.
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Q:
1)Is it possible to get unlocked chip to programm MLX90316 SPI on the board? Things like sensor Front-End parametrs (see Spec page 20).
2)If it is possible, where I can get Control registers Adresses? Or how to access those Control bits thru serial post? Spec I have(3901090316 rev 003) has no indications how to do that.
Issue resolved.
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Q:
I have an application where I need to be able to set the discontinuity point in the field via an attached microcontroller. Where can I find programming specs for thed 90316?
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A:
Melexis does not recommend in the field reprogramming of our IC's. It has been our experience that this activity brings excessive risk to the reliable and proper operation of the IC. We only support programming the device using the Melexis PTC-04 programmer and software. Through this tool we are able to assure customers achieve consistent and correct behaviors of the IC. Therefor the programming details are not made available.
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A:
Programming of Melexis Hall sensors can only be done through the PTC-04.
Changing the DP, is equal to addeing a constant to the angle measurement ( New angle = Angle -DP ), which you probably can easily do in the attached micrcontroller. Creating a complex programming protocol compared to a simple mathematical calulation will take much more resources and create more errors.
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Q:
Good morning, i'm the electronic designer at Elen srl, Garbagnate Milanese Italy, our development group is
evaluating your component named 90316.
We are using your PTC04 programmer together with your toolbox application.
Using the "measurements" command we have seen we can monitor the change in voltage on the output OUT1
(8 pin chip version) as the magnet rotates upon the chip surface, when the component is unprogrammed and then in
the full 360 degrees range.
Verified this behaviour, we are trying to pass to the second step, and then customize the behaviour of the 90316
to satisfy our application goal.
First of all, we've read (it seems non so carefully as we think) the program solve flow and the example showed
in your documentation, but we can't obtain the desired behaviour of the component.
It will be very useful to receive from you the list of programming values related on the 100 degrees application
showed in the datasheets as a guide
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A:
The best way to start programming the MLX90316 for your application is to use the user interface/ solver procedure.
Use the following sequence for a 2 point calibration:
- New device
- Set settings ( output , rotating direction,..)
- Characterize ( in case of analog output)
- Search RG
- Move the magnet to the first calibration point.
- Set point A ( angle point A= (360-100)/2=130deg; level point A = 10% )-> clamping low = 0..130; clamping high = 230..360 deg.
- Move the magnet 100 deg to the second calibration point.
- Set point B ( Level point B = 90%)
- Finish program cycle.
If you readback the EEPROM - Linear setup parameters, you will see the following results :
A_X = 130 deg; A_Y=10%, S0=A_S=(90-10)%/100deg=0.8%/deg;
B_X = 130+100deg; B_Y=90%; B_S= A_S
C_X= 360 deg ( not used)
|
Q:
See the document"0004998_Solver_Flow" ,Page1's flow chart, "Characterize the Output of D/A Stage" is recommended,my question is
1) How to use this Characterize method and results,i.e. Offset and Gain?yes, the Labview demo you supplied does call this"CharacterizeOutputDAC" Method one time when the Outputstage Button is clicked,and
followed by two "GetSolverSetting" Method to display the Gain and Offset on the Demo's frontpanel,and such result seems
never be used any longer during set Point A,B,C.Correct?
is it necessary to call extra two "SetSolverSetting"to store its Gain and Offset?
2)about the "ProgramDevice",it is said that this method just store/update the Cache's data into EEPROM,correct?in another word, SetCoordinate A,B,C methods will just store the data into Cache instead of 90316's EEPROM, correct?
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A:
1) The CHARACTERIZEOUTPUTDAC method calculates coefficients OutputDacGain+ OutputDacOffset for level correction, and will be used in all calculation of the output level in %Vdd. This method will program and measure the output at 10 % & 90 %Vdd, and calculate the gain + offset.
All subsequent calls to SetEEParameterValue method will calculate the level value to store in the EEPROM by using the following formula:
DAC_Value_EEPROM [%VDD] = Requested_DAC_Value [%VDD] * Gain + Offset
All subsequent calls to GetEEParameterValue method will calculate the level value from that in the EEPROM by using the following formula:
Returned_DAC_Value [%VDD] = (DAC_Value_EEPROM [%VDD] – Offset) / Gain
So if you use this method after the new device method, all the necessary corrections are automatically performed for you, also with the solver method like SetCoordinateB( %Vdd).
NOTE: Also for all solver functions, only the selected die is taken in account!
NOTE: The level correction will be reset after the New device method (Gain=1/Offset=0)
2) Indeed, during the solver steps or with the SetEEParameter method, you will only update the cache of your PC and the device is programmed with the changed EEPROM parameters only after the ProgramDevice Method.
|
Q:
In the data sheet of Mlx316, the item 14.1.1.
"Analog Output Mode
The Analog Output Mode is a rail-to-rail and ratiometric output with a push-pull output stage configuration allowed the use of a pull-up or pull-down resistor."
Does that mean the resistors are inside PTC04?
And in the auto-calibration mode of user interface, there are two parameters ("pull-up", "pull-down") could be used by users.
When should the two parameters be used? And if we use one of the parameters, for example, "pull-up", whether we need to use a pull-up resistor in the application circuit? Or in other words, if we need a pull-down resistor in the application circuit, whether we need to make the pull-down parameter valid in the auto-calibration mode of the UI?
Would you please explain these items? Thank you very much.
|
A:
The 90316 output stage can be used with a resistive pull-up or pull down load ( min 4K) and depends on the customer’s application. In case of a fault like broken Vdd, the behavior of the output ( item 15 in datasheet ) depends on the load.
For automotive applications the resistive load is present in the ECU and not on the PCB of 90316, and therefore we have foreseen the possibility to apply this load during the calibration of the device. On the DB90316 we have added the possibility of applying a 5K6 PU to a programmable battery voltage or a 10K PD. This is optional, and if you require other values then the default, you can also add the load externally. The programmable battery voltage ( PPS3) is also available on the DB25 connector of the PTC-04.
So if you have a pull-up resistor at the output of the 90316 in your final application, then I recommend that you also apply this load during the calibration. (Internally or externally), since the results of the “characterize DAC” can be influenced by the load.
|
Q:
I tested the MLX90316 with PWM mode. and noticed the error of eeprom, error was "CRC programmed in the EEPROM is bad", when I find the error message in the EEPROM read state, MLX lock was activated, so, PWM frequency was not changed. but some chip of MLX90316 was not activated the MLX LOCK box, these chip was programmed PWM mode, frequency was changed sucessily.
the difference of each chip was code that marked in the surface of chip.
1.I want to know the chip marking method,
in the datasheet marking method was different with real chip. datasheet is nerest version. (october 2005 version)
2. what's means the CRC was programmed in the EEPROM is bad ?
3. why some chip was not activated MLX LOCK box in the eeprom screen and some chip was activated ?
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Q:
could you advise me, please, with which version of the MLX90316 you are actually working and what is mentioned on the package of the ICs, which are working, and on the ICs, which are not working.
|
A:
1) The chip marking should normally be :
316BAD , equal to Partnr 90316 - Version BAD
820345/X1, which represents the Lot number
Please check the latest datasheet for more information
The lotnr can of course be different from lot to lot. If you have different numbers, then it means that you received parts from different lots.
2) The EEPROM of 90316 contains a CRC check, and this should be correctly programmed so the test will pass and the device will work correctly. In case you have an un-programmed and relatively old device, then it is possible that the default CRC value was incorrectly programmed and you receive an error the first time you perform the readback of the EEPROM. Every time when you change a value in the EEPROM = program the device, the CRC is recalculated and updated. So the initial error should disappear. We know that this was a mistake in the first delivered parts, but would be solved when the parts is finally programmed by customer. The reason why you see the error must be the combination of a relative old samples and the latest software which performs this extra check.
3) Initially we had enabled the extra lock of the EEPROM parameters for the Melexis area, but then the PWM frequency could not be changed. Again, this is only the case for the relatively old samples. All devices that we delivered for the past year do not have the Melexis lock and the user can change the PWM frequency. When you start with “New Device”, then the PWF freq setting will be disabled/ enabled depending if the Melexis lock had been programmed or not.
|
Q:
Is it possible to calibrate the gains and offsets of the analog chain before the local micro does the arctan function?
I am confused by the lower limit of magnetic filed strength. Is 20mT the smallest peak value (north or south directions) that the sensor should see to get good performance?
|
A:
Yes, the field range that the 90316 should see is 20..70mT, over the complete temperature range. Lower fields will influence the performance; higher fields will saturate the IMC and induce additional nonlinearity errors.
The 90316 will automatically adjust the gain in the application, based on the measured field.
|
Q:
What is the procedure to read the internal SIN & COS values of the current angle (two words of 16bits) via the SPI bus?
|
A:
Via the SPI bus the 90316 only sends the calculated angle (14 Bit). It is not possible to program or get additional information.
Only in case of an error, the angle information is replaced by the error code (16 bit).
|
Q:
the magnetic field evaluation is measured by chip and showed by RG value, if in UI 90316 result is constantly "15", it's mean field is too low. i'm surprise because I use a strong NdFeB 45a for testing and gp distance is 3 mm!!
As I know you suggest with SM6SmCo magnet operating distance range for 2 to 5 mm. Could you give me your opinion about it ?
|
Q:
I have the same problem, mine also just show 15, and i know that the fieldstrength is strong enough, because it measures correctly....
|
A:
- If you use a strong diametrical magnetised NdFeB magnet at 3 mm, then you should indeed have a rough gain < 15.
- But if you get a value equal to 15, this still means that according to the device the field is too low.
- Since I do not know your setup or how the device has been programmed, it is difficult to say what could be the problem. I would suggest to first checking if you use the correct software and then manually check the field strength:
1) Readback the eeprom and make sure that AutoRG is enabled and DisableFG is off. Check that SPI is switched off.
2) Reset the device
3) Goto RAM reading and check the Fine gain + rough gain. This should be changing when the airgap changes.
|
Q:
I follow your remark but I'm going into worse situatiom
Know i can't anythink read in RAM and when I check RG value " setting rough gain failed: reason PTC04 received from the chip ACK/err =00H
While writing to address 0072h
I cannot restore previus setting also
|
Q:
I've got exactly the same problems as you, I neither can't read from any of my devices (MLX90316). I also get that error and I can't solve it in any way, I've tried 7 different devices, but they all just gives me that exact same error. I neither can't read the EEPROM in any of my devices!!
My programmer has been working just fine for a long period, but suddenly it started giving me these problems, so I guess that my programmer is broken, so I have just sent it to Melexis for repair.
I have tried EVERYTHING to fix it, but no luck, so I hope that it's the programmer that fails.
|
A:
From your reply it seems that the communication with the 90316 has been affected and this should not been the case by following the instructions.
1) I assume you first checked that you used the correct software? UI 90316BAD rev 1.07 or 1.11
2) If the read back of EEPROM was successful, then the communication is verified. I asked to check that AutoRG was set. Did you change any other parameters from the EEPROM? The procedure to change EEPROM parameters is explained in the UI documentation, page 10.
If you can confirm that both steps are performed correctly and the connections with PTC04 are correct, you should be able to communicate with the device.
|
Q:
here sw veification revision dependance:
1) UI 090316DB 1.7
know I follow correctly UI doc, and I'm able to communicate with device. :-)
But, something strange appear: no variation on OUT 1A mux, i'm try with several calibration point of linearity transfer function like weeks ago, but the only change is: if I set level point A 50% of VDD, V out mux remain constantly on 50% of VDD. Have you some suggetion about it...
|
A:
- If I understand correctly the communication is OK now and you get a RG < 15.
- The output should respond as you have programmed it, so please check if you have followed the procedure correctly.
1) New device
2) Set settings
3) Characterize (only for analog output) Gain must be around 1.01, and offset around -0.3%.
4) Search RG. Must be < 13
5) Angle point A=0; Level point A = 10%, Set point A.
6) Rotate your magnet 180 deg in correct direction and set level point B = 50 %; Set point B. Check the datalog in MPT if results are acceptable.
7) Finish program
Goto measurement and enable Out1mux and angle.
Both values should change if you rotate the magnet.
Let me know up to which step of the procedure it was successful without errors.
|
Q:
now i'm on track more. I'm able to finish first test, and result was excellent
Next experiment is to use 90316, in same apppplication but with greater angle variation and at highter speed, so angle change at max 80hz. From PTC04 and soft i can read nothing From which pin I can with scopemeter recorder variation?
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A:
I am not sure that I understand your question so I will give a general answer.
The communication with the PTC04/90316 goes through the output pin. During programming the Vdd=7.5V and output pin is then used for digital communication ( 0 / 5V). If Vdd =5 V, the output is back in normal mode and should respond to variations of the magnet according to the programmed EEPROM parameters.
If you use an external 5V power supply, then you can connect the scope to the output pin (pin5 for SO8) and check the changes. In case you use the PTC-04, there should be no communication (and mux switched off) and the Vdd must be set to 5V. The best way to guarantee this is to use the measurement menu and select Vdd + out1. (Deselect angle).
|
Q:
One question:
in all of your materials about MLX90316, the magnet is rotating CCW,may it rotate CW? If so,will the accuracy decrease?
thank you!
|
A:
Yes it may and no the accuracy will be the same.
|
Q:
Is the MLX90316 commercially available? If so from where?
Does it operate in saturation mode? Or do I Have to have a very specific a) magnet size b) gauss (or Oersted) rating c) distance from the sensor?
Also, the datasheet states that the SOIC-8 package has one output. Analog is 12-bits resolution (so I'm assuming my 14-bit data acquisition unit will be able to see 0.088 degrees resolution). However for a full 14-bit resolution, some sort of serial protocol is required. Is there any simple way of doing this? I am using a national instruments USB data acquisition unit.
|
A:
MLX90316 is commercially available and you can get it through our sales network. If you want to know the nearest one from your location, please browse to the following link:
http://www.melexis.com/contact.asp
Please refer to the datasheet to get an overview of the working principle of this Triaxis IC:
http://www.melexis.com/prodmain.asp?search=mlx90316&family=MLX90316
If the Integrated Magneto Concentrator (IMC) is not saturated, it will not introduce any significant non-linearity error. However, if you saturate it, the output of the IC will show a large non-linearity error (the signature of this error is 4 periods over a full 360 degrees revolution).
The saturation starts above 70 mT. In other words, you need to make sure the magnetic flux density at the IC level is less than 70 mT to avoid saturation effect.
|
Q:
I've realized a 120 deg. sensing using the MLX90316(dual die)
I used two outputs, one analog and the other is PWM, the system worked in a great way. Now I have a new project and I should read a 360 deg.
but in serial mode, I started trying and collecting data using analog output, the 360 deg. is acheived but I still have problems with serial protocol.
My microcontroller program acts as follows:
-the sequence AAFFh
is put on the out1 pin
-the same microcontroller pin is defined as input and 64 clocks are put on the clk pin
- no output data (on out1 pin)are displayed on the oscilloscope.
I don't know where the fault is, I give the higher probability for the program of the MLX,if anyone Knows how to implement serial communication please notify me.
|
Q:
Another notice, if we use the ciruit drawn in the datasheet(page 26 & 27) with the stated control(page 23,timing diagram) at the MOSI output we will be forcing the MISO input to logic low level and the data will be lost.
and also the data sent as a request(AAh)
will be inverted and will be 55h, so what is the correct way to control the MLX90316.
|
A:
The 90316 responds only if all requirements are fulfilled. Please check the following:
- EEPROM parameter SPI is set.
- Check application diagram as described in datasheet
- Check capacitors on out1 ( MOSI/MISO) , out 2 (SCLK) and out 3 (/SS). Typical 1nF. To big capacitors will jeopardize the timing specifications.
- Check signals at pins 90316 on scope. ( /SS = low, SCLK = 80 Clocks and AAFFh as startbyte during falling edge of clock.) Note that your uC has to send 5500h on mosi because of the transistor.
- Check signal levels ( 0..5V ).
- Check timings according to specifications in datasheet. Verify EEPROM if 90316 is set to low / high speed mode.
In case you do not get any respond (angle nor error code), then I would advise to create a scope plot of the 3 signals + screendump off EEPROM parameters and send it to me.
|
Q:
I took some data from the MLX90316 serially but checking bits after positive edges, when I recieved your reply,I tried the falling edges but no data is displayed, so I returned to my old method.But I have some errors in it, the errors are not repetitive (the time between erronous data is not constant, the magnitude of errors it not constant)
so if you have any idea about this phenomena please support me with.
|
A:
The positive going edge of the SCLK shifts a bit to the Slave’s output stage ( =90316) and the negative going edge samples the bit at the Master's input stage. This means that the value is only stable during the negative going edge and will toggle during the positive going edge.
Please check the serial protocol mode of 90316, as described in the dataheet on page 21, and the timing diagram on page 22.
You mentioned that during the falling edges no data is displayed. Can you verify that the uC Mosi is low during the reading of the data? It would help if you can send me a scope plot of the 3 signals. A scope plot is the only helpful tool to check the signals and timing of the SPI communication.
|
Q:
I tried to add a capacitor and resitor on the
output of the 90316 asif in analog mode, and the errors have been disappeared.with respect to your last reply,I'm sure that the out1 pin is floating when reading data, since I didn't use the circuit drawn in the datasheet, I used a circuit using one pin of the uC and I'm sending 16bit and then declare the pin as input and read 48bits.
|
A:
Since the errors have been disappeared with adding a cap / resistor, the root cause of your problem is most likely the signal levels. As mentioned in my recommendations the levels on out1 & out2 of the MLX90316 should be in the range 0..5V, or actually between GND and VDD of the device. This should be checked using an oscilloscope. The MLX90316 has build in diagnostic features and monitors the level. In case the output level exceeds these threshold levels, the device is in error mode.
To guarantee good communication we recommend to add 2 resistors on out 1( 1K / 20K as a voltage divider) and a series resistor of 100 ohm between uC and voltage divider.
|
Q:
My question is are the SPI Levels for 3Volt Apps. applicable? Or must the Levels have 5Volt?
|
A:
- The levels on MISO/MOSI , CLK and /SS can be 0/3V.
- Vdd of the 90316 is 4.5-5.5V
|
Q:
Hello sir,
I am using MLX90316 for my application.I have only MLX90316 part and now i want to do it with SPI ( in VHDL) interface.Do i need any extra part for making in SPI mode??
In my code,
i divide my clock in 80 cycle. when clock toggle on postive then i am sending one bit from Master to slave (10101010 so first bit is "0") and negative clock edge i am receiving one bit from slave to master. in second clock on positive edge, i am sending bit "1" and negative clock edge i am receiving bit from slave to master.
Is it correct method for SPI interface or not ??
Or i have to send 55H on first time (on every positive edge) and after this byte only i have to receive (No bit from master to slave / or send only "00"h) every positive clock edge..
Please, Help me out..
Thanking you.
|
A:
Hello Munna,
The Master should send AAh (55h in case of inverting transistor) followed by 9 bytes FFh. The Slave will answer with two bytes FFh followed by 4 data bytes and 4 bytes FFh.
PTE.
|
Q:
Thank you sir for your reply.
Ya..I know that master should send AAh but do i need to send 1 bit on positive edge clock from master to slave or do i need to send whole byte (AAh) and then recieve from Slave??
Sorry for this question but i am new in this field.
Thanking you.
|
A:
Hello
The SPI is a digital serial protocol, and the convention is that during the positive going edge of the clock, the data may change and on the negative going edge the data-bit is sampled.
So the master sends all the CLK pulses ( 10 bytes) and starts with 2 x 8 clk pulses for sending the 2 start bytes. During these 16 clk pulses the mosi line should be AA followed by FF. So the first negative going edge, the data line is high (=1) and the next negative going edge the dateline should be 0, etc. … (10101010) During clock pulse 9..16 the data line should be high. Now the 90316 has received the 2 start bytes and is ready to answer.
During the following 8 x 8 clock pulses the 90316 will answer, starting with 2 bytes of data, 2 bytes of inverted data and 4 bytes were the data line stays high. During every negative going edge, you need to read that data bit by bit.
Hope this helps to understand the SPI protocol of 90316.
Rg
JC Depoorter
|
Q:
The datasheet for the MLX90316 states that the discontinuity point (DP) can be set by the user. The default value for the DP is 0. How is the DP value modified?
|
A:
The DP is a value between 0-360 degrees and can be programmed manually or is calculated automatically with the point A of the solver sequence.
Also check AN "Back-End Calibration of MLX90316 ", pag 3 for more information.
http://www.melexis.com/Asset.aspx?nID=5288
|
Q:
I have the evb90316 and the only output I can get is all 1's or all 0's depending on the position of the knob. What am I missing?
|
A:
By default the EVB90316 is programmed with an analog output = 10-90 % Vdd. Unless there was a special request to reprogram it for SPI, the EVB is not useable for digital mode.
|
Q:
OK, missed that in the datasheet. Just saw the ss,sclk and mosi reference and ASSumed the spi. I'll hook it up to an adc tonight and see what I get. Thanks.
|
Q:
I am having some problems with using the 90316 SPI with a Atmega168. I was using the schematic shown in fig 16 that uses the mosfet. I just noticed that the mosfet is not applicable because the AVR does not have open drain capability. Now, I am reading that a transistor should be used. What transistor and how should it be connected? Also, is there any AVR example code?
|
A:
The table 3 on pag 34 and the connection diagram fig 16 are applicable for all SPI applications.
So if you are using a Micro-controller without open-drain capability (like ATMEL AVR ), then you need to use for example a BS170.
I do not understand your sentence : "I just noticed that the mosfet is not applicable because the AVR does not have open drain capability". This is not true.
|
Q:
Ok, thanks for clearing that up. Row 4 in table 3 on page 34 was confusing me. It says MOS type N/A.
|
Q:
I've got a problem with the SPI interface of the MLX. The timing is very "specific". To get the exact Timing I have to implement timers and because of that I have to handle Interrupts.
Is there any easier way to run SPI with the MLX?
|
A:
The timings mentioned in the datasheet are the minimum timings. Actually you have a big margin and there is no need to excatly uses these timings as long as there are not smaller then the specifications.
|
Q:
thanks for your answer.The SPI interface is running. I made a fault in the dataframe.
|
Q:
I noticed on the datasheet for the 90316 that the MISO/MOSI share the same line and communication is possible with the MOSFET. But in the command device mechanism section (16.10), the master is suppose to send FF's while receiving data. If the Master/Slave are sharing the same line and the master is sending FF, wouldn't that make everything from the slave drive straight to ground (since the MOSFET will be "closed")? Wouldn't it make more sense to send 00s so that the data from the slave is actually received on the MISO pin?
|
A:
Hello,
The description in the datasheet is maybe not so clear and will be improved, but you are correct about the implementation.
The data frame structure is describing what signals should be on the common line ( or at pin5 of the 90316). Microcontrollers without open-drain capability need an external transistor and the signals of MOSI are inverted.
So the master needs to send 55h 00h, and on the common line you should have AAh FFh.
|
Q:
There is no detailed information in MLX90316 datasheet about the SPI logic levels. I understand that they are +5V tolerant, but are the switching thresholds TTL or CMOS compatible, or more specifically is it possible to drive the SPI inputs directly by a +3.3V processor device?
|
A:
In the datasheet there is indeed not a clear description of the input levels.
On the application diagram ( fig 16) you can see that the pull up voltage is 3.3/5V.
The SPI input levels /ss , CLK , Miso& Mosi are indeed 3.3 V compatible.
However the Vdd spec is 5V +/- 10 %.
|
Q:
The MLX90316 is specified for 4.5V to 5.5V according to the datasheet. In the schematic drawing of the chip there is a 3V3 voltage regulator inside. I have a system with a board voltage of 3V6. To avoid energy loss when up converting to 5V, my question is if it is allowed to run the MLX90316 with 3V6. My testing showed that MLX90316 works well with 3V6 too.
|
A:
Indeed, the chip is operational at 3.6V but the device is internally not yet stabilized. The current Idd is still increasing with increasing Vdd and the voltage regulator is still in "follower mode"
The normal operation mode is 4.5-5.5V, and this is the range were the chip is qualified. I am afraid that your test is probably a quick check at room temp, and not a qualified life time test between -40C and 150C.
|
Q:
When I programmed the 316 by using the libview VIs provided by Melexis, some parameters(especially the "LNR_Y" and "Slope") read from the EEprom didn't equal to the value that they should be. For example, when programmed the parameters of "LNR_Y" and "Slope" with the value "12.8" and "4.2", but when read them by using the EEPROM tool of UI of 316, the two parameters are "12.7" and "4.21". But if programmed the parameters with UI, then there is no tolerance occured. Do you know what is the problem and How to solve it?
|
A:
First there is the program resolution of the parameters that can create a small difference between writing and the verification. The resolution is very high, but existing.
- Resolution slope = 2.5 E-04 % / Deg
- Resolution output = 1.5 E-03 %
Secondly, in case of an analog output, the values are corrected with the outputGACgain and outputDACoffset ( See also UI pag 9 - Output DAC).
When you start the software or execute "Device replaced / New device”, the DACgain and DACoffset are set to the default values Gain =1 and offset =0.
The function "characterzeoutputDac" will find the real gain and offset of the D/A converter and these correction values will be used during programming and reading of the linear transfer function parameters, to match the theoretical values with the real output voltages.
|
Q:
If I want to program my 90316 to output as the below :
5V @ 160 deg
0V @ 180 deg
5V @ 200 deg
And linearily decrease and increase
from 160 thru 200 deg
(the pattern is just like a 'V' )
Is it possible?
|
A:
It is possible to have positive and negative slopes of the transfert function only if the negative slope is after the C point. So, you have to change the discontinuity point parameter to get the following:
A point: 0 degrees - 0 %Vdd
Slope after A: 5 %/deg
B point: 20 degrees - 100 %vdd
Slope after B: 0 %/deg
C point: 340 - 100 %Vdd
Slope after C: - 5 %Vdd
Take care if you are using 0%Vdd and 100%Vdd because the rail to rail is never 0 %Vdd and 100 %Vdd.
|
Q:
I have the same issue too, but I don't understand your reply, can you explain them for details?
|
A:
The transfer curve of the 90316 can be programmed with 3 points and 4 slopes. Since your application requires a negative slope ( - 5 %/deg) , this is only possible with the slope after point C.
So you need to program the lowest value ( 0%) at the 0 degrees and define this as poin A.
Then the moving the magnet +- 2 degrees, the output will increase.
340 deg = C. .B = 20 deg
. .
. .
. .
.A=0 degrees
|
Q:
Where can I get the diametrally magnetized magnet required by the MLX90316 in the US? Please suggest some US suppliers.
|
A:
Here are a few commercial scale magnet sources. While there are endless numbers of online magnet companies who can sell a few to a few hundred stock magnets few of them are suitable as suppliers to be used in a commercial sensor manufacturing project. If your challenge is to find such a partner then review some of these web sites and companies. Keeping in mind that the magnet industry is constantly undergoing merger and acquisition and some of these companies may change names or be acquired and become divisions of other companies.
But here are a few resources to check out beyond the one you have found on your own.
http://www.arnoldmagnetics.com/
http://www.hitachimetals.com/product/permanentmagnets/neodymium/
http://www.edyne.com/
http://www.magnetsim.com/
http://www.eamagnetics.com/
http://www.intemag.com/magnetmaterials/magmat.htm
http://www.vaccorp.com
http://www.adamsmagnetic.com/
http://www.mmcmagnetics.com/
http://www.ecs-global.net/p_magnets.html
http://www.tdk.co.jp/tefe02/magnet.htm
|
Q:
I want to use MLX90316 in a Steering wheel wiper command. The problem is that the lever rotate only 4 degress per position. I think that your sensors can manage this angle (the resolution is up to 14 bit) of rotation but i just wanted some confirmation from you.
|
A:
Tha ADC resolution of 90316 is indeed +/- 14 bit in low speed application, but it is typycal a 12 bit, 360 deg rotation sensor.
It can be used for smal angle applications, but if you have a 4 deg application, then the typical temperature drift of +/- 0.4 deg will be equal to 10 %.
|
Q:
I saw an app note somewhere on the Melexis website about how to use two 90316 devices on one spi port.
The app note showed how data from both devices can be retrieved using one message sequence by configuring one of the devices to transmit its data during the last four bytes of the 10-byte data block. Apparently this capability is supported by doing additional serial communications to one of the chips with an opcode that is not described in the data sheet.
Can someone send me a link of how I can find this document?
|
A:
As far as I know there is no such AN on the Melexis website (yet). You probably have seen a document that mentioned this possibility. Since I cannot post any pictures or drawings, I will send you a direct mail with more information.
|
Q:
I also am using two 90316 SPI devices. Based on the SPI protocol drawing on page 29, I'm assuming that as long as each device has its own /SS, I'm ok. A device with /SS high should ignore all the other signals, right?
|
A:
Indeed, using two 90316 SPI devices always need two /SS lines, since you need to be able to select each individual device. When /SS is high, then all signals are ignored.
|
Q:
I'm trying to develop a Labview program to automate programming MLX90316 devices during in-circuit test. From the document entitled MLX90316 PSF Software Library I have identified a number of methods associated with the MLX90316PSFDevice object which pertain to programming EEPROM parameters. However none of these seem to work. Most EEPROM parameters in fact seem to be unsupported according to a constants table at the end of this document. If any of this makes sense to anyone I would be very grateful for any assistance.
...I forgot to mention I am using the PTC04 programmer with the MLX90316 interface module. I have already successfully programmed quite a number of these devices "manually" using the MPT Programming software so I am reasonably confident that my hardware is functioning correctly.
|
Q:
Hi, I'm trying to develop a Labview program to automate programming MLX90316 devices during in-circuit test. I am using the PTC04 programmer with the MLX90316 interface module. I have already successfully programmed quite a number of these devices "manually" using the MPT Programming software so I am reasonably confident that my hardware is functioning correctly. From the document entitled MLX90316 PSF Software Library I have identified a number of PSF methods associated with the MLX90316PSFDevice object which pertain to programming EEPROM parameters. However none of these seem to work. Most EEPROM parameters in fact seem to be unsupported according to an "enumeration constants" table at the end of this document. When I try to use the GetEE/SetEE.. methods I get an "invalid parameter" error. would be very grateful for any assistance. Thank you.
|
A:
- Did you set the ChipVersion property? Some parameters only work with certain versions of the chip. You will get an error if this is not set correctly. See section 7.33.4 of the PSF documentation
- Did you notice that some parameters only work with "SetCode" and not "SetParameter"
|
Q:
Yes, I set the ChipVersion to "BAD" (type 3) to match the MPT UI that came with the programmer (UI-MLX90316BAD). Having done this I have managed to access pretty much all the EEParameters now except CustID1 and ResetOnFault.
I suspect however that the ChipVersion property is still the cause of the problem because the IC version in my application is "BCG" (type 5 I think!). The MPT UI works correctly - the problem only occurs with the Labview program. When I try to set the ChipVersion property to BCG (#5) I get an "invalid parameter" error. Is there a BCG version of the API that I need to install. I can't find any reference to it on the website.
|
A:
- Please check that you select / set the correct chipversion after initializing PTC-04. If you use 90316 BCG , than select chipversion =6 with the latest library ( PSF90316). You can download the software from softdist.melexis.com. If you do not have a softdist account yet, send me a mail with the request.
Programming 90316BCG with 90316 BAD software will work in most cases, but there is a small change that you will see something unexpected.
- Use the invoke method "GetParameterCode"
The following EEPROM parameters are actually available in all versions, so it should always work.
CodeCUSTID1 / EEPROM parameter 22 / EE_CUST_ID1 EEPROM cell
CodeDRESONFAULT /EEPROM parameter 52 / Disable Reset on Fault
|
Q:
I have a problem with the MLX90316 angle measurement.
My application is the measurement of the rotation angle from induction motor. Communication via SPI. Most of the angles are displayed correctly but sometimes the values jumping back. e.g. 338..339..321..322....360..0..
Errorcode is not detected!
Is this a known problem? What can I do?
|
A:
So far this problem is not known.
Most likely it is related to a programming or communication error.
If you detect the problem with regularity then it is linked to a programming / saturation error, otherwise I think it is a communication problem.
1) Communication error
If the error code is not detected, you confirm that you checked the lsb of the 2 data bytes to be equal to 1.
Can you also confirm that you checked the communication and that all 4 data bytes are OK? (i.e. 2 Data bytes + 2 inverted data bytes = FFFFh)
2) Programming error
- can you check the programming of the transfer curve with the PTC-04 or did you receive pre-programmed parts?
3) Saturation
Please check that it is not a linearity error with a sinusoidal shape over 360 deg.. If you detect a 4 period sinusoidal linearity error, then the magnetic field is to strong and you should reduce the magnetic field density.
If you cannot solve the problem, please send us ( Melexis or your local rep) some raw data to analyze.
|
Q:
The problem is solved!
The SPI- Bitrate was to high.
|
Q:
What is the purpose of the Vdig pin on the MLX90316? What is the purpose of decoupling to ground? What happens if this connection is broke?
|
A:
This is the decoupling for the internal voltage regulator. If this pin is open, there will be increased noise in the system.
|
Q:
I´ve got questions about the MLX 90316.
In the front-end calibration of MLX90316 is a figure (page 7) which shows the relationship between the angular position an the linearity error.
First question: Exists a formula to calculate the relationship between the field strength and the linearity error. For e.g. a field strength of 100 mT causes an linearity error of 7%
and a field strength of 120 mT causes an linearity error of ????
Second question: The conversion from linearity error to angular error. For e. g. a non-linearity error of 1% leads to an angular error of 0.15 degree
and a non-linearity error of 7% leads to an angular error of ????
Third question: What is under a field strength of 20 mT. You told me that the noise to signal ration will increase. Does also exists a relationship between the field strength and
the non-linearity. For e. g. a field strength of 10 mT causes an linearity error of 1% and so on. Exists a formula to calculate this relationship and to converse the non-linearity into an
angular error?
Last question: Can you send me the back-end calibration of MLX90316. I searched on the melexis homepage, but I didn`t find anything.
|
A:
When the field is increasing, the concentrator starts to saturate in the center, and the saturation will be visible mainly in the Y-axis when applying a flux in the X-axis and vice versa.
This is complex phenomena that we have characterized by measurements of the X an Y signals, and not by using a formula. Based on the measurements we know that the typical relationship of the nonlinearity ( NLE) vs the field ( B ) is a expositional function [ NLE = 0.0004 x e^(0.0973 x B) ]
- The relationship between the max angle error and the nonlinearity was simulated based on the knowledge of the characterization measurements ( NLE vs field) and confirmed by measurements. The signature of the nonlinearity error is 4 period over 360 degrees.
The typical relationship of the max angle error vs field is [angle error = 6E-05x e^( 0.0961 x B) ]
- In case of a 10mT signal , the nonlinearity and angle error is negligible small. But because of the low field , the gain is increased to a very high level and therefore the noise and offset will become the main players of disturbing the sin and cos signals.
- The AN for the back end calibration is under development.
|
Q:
I want to use MLX90316 to measure relative rotation between two angular position. For me it is not important the absolute angular position but the variation beetween positions. In this case what is the minimun relative movement that i can measure (considering the max error introduced by MLX90316)?
|
A:
The minimum movement you can detect is limited by the noise and the resolution. The specifications are listed in section 10 of the datasheet.
In Slow Mode, Filter=5, the maximum measurement noise is 0.06 degrees. This is the maximum noise for SPI output mode.
For analog output, there is an additional output stage noise of 0.05%. You can convert to degrees by dividing by the output slope (programmed in %/degree).
For analog output, the maximum step size is 2LSB (according to the DNL spec). 2LSB * 0.025%/LSB = 0.05%. Divide by the output slope to convert to degrees.
The other linearity errors are not significant over such a small angle span.
|
Q:
I have got a sample of MLX90316KGO. And I'd like its output curve as Die A is Positive and Die B is Negative. How can I do? I have tried many times but it seems the chip can not support negative curve. On the topside of chip it marks 316BAD, 850690 ,X5. Would you please help me with this question?
|
A:
The 90316 (Chip mark : BAD) can indeed only have positive slopes. However the rotation direction is programmable, which means that we can convert a negative slope to a positive slope by inverting the original rotating direction.
Please also check pag 9 of the application note : Back-End Calibration of MLX90316
You did not mention your application angle span, so I will give a general programming procedure for a 90 degrees application with the 90316 User interface. ( See also AN)
Die A & B : New device
Die A & B : Select Clockwise ( or CCW) for both dies, and all other solver settings
Die B : Select neg(ative) slope !!!
Die A & B : Set Settings
Die A & B : Characterize , in case of analog output
Die A & B : Search RG
Die A : point A ( 135 deg , 10 % ) ( First programming point of die A will start at 10%)
Die B : point A ( 225 deg , 90 % ) ( First programming point of die B will start at 90%)
Die A : point B ( 90 % )
Die B : point B ( 10 % )
Die A & B : Finish program
Note : The linear graph will also not show the negative slope. You can check the EEPROM parameters and will notice that the rotating direction of Die A is different from Die B.
|
Q:
Following your calibration step I can get negative out. Thanks!
|
Q:
I'm searching for information about the frame I have to send to the sensor when using SPI mode.
|
A:
The datasheet of 90333 will be updated shortly and will give more detailed information.
In the meantime here is a description of the data format when the line /SS is low :
Case 1 : ( XYZ = 0)
1 start byte FFh ( = only send 8 CLK pulses)
2 data bytes (MSB first) Alpha
2 data bytes (MSB first) Beta
2 data bytes (MSB first) Error Code
1 SUM byte 8 LSB of the sum of the transmitted bytes
Case 1 : ( XYZ = 1)
1 start byte FFh ( = only send 8 CLK pulses)
2 data bytes (MSB first) X
2 data bytes (MSB first) Y
2 data bytes (MSB first) Z
1 SUM byte 8 LSB of the sum of the transmitted bytes
|
Q:
Thank you for answering me but i'm asking for the frame the master has to send to enable the sensor to respond. For example for the 90316, the master sends AAh followed by 9 FFh. Is it the same frame for the 90333?
|
A:
For the 90316, the master needs to send 2 start bytes AAh & FFh. The total dataframe is 10 x 8 CLK pulses long.
For the 90333, the master needs to send 1 start byte FFh, which is equal to keeping the MOSI line high during the complete dataframe.
The total dataframe is 8 x 8 CLK pulses long.
|
Q:
Can I have a copy of the look up table used to compute the atan(by/bz) for this chip.
Is it possible to modify this table in case we find the need.
|
A:
The LUT is inside the firmware of the 90316 and is not accessible and not available for changes.
Firmware changes are only possible by modifying the last two steps of the wafer process.
|
Q:
I am looking at building the MLX90333 into a design and there are several things that are unclear from reading the datasheet:
1. Can I program the parameters listed on page 18 of the data sheet? If so, how is this done -- there does not appear to be an explanation for this on the site. I stumbled across the PTC04 programmer -- must this be used? Do I have to buy a piece of hardware to program every part?
2. What protocol is used to obtain the readings from the sensor? Is the SS line just lowered and then the data is shifted to the uP (in other words, the MOSI line is really just a slave-to-master line in spite of the name)?
This part fits my application, but I'm having a devil of a time reading this data sheet and figuring out how to talk to the MLX90333...
|
A:
“The programming steps do not require any dedicated pins. The operation is done using the supply and output nodes of the IC. The programming of the MLX90333 is handled at both engineering lab and production line levels by the Melexis Programming Unit PTC-04 with the MLX90316 daughterboard and dedicated software tools (DLL - User Interface)." (Pag 12 of datahseet)
1) Yes, MLX90333 End-User Programmable Items means that all these parameters can be programmed by using the PTC-04.
Melexis only supports programming the MLX90333 through the programmer PTC-04 and you will need to buy this equipment. Please contact your local rep for additional information and pricing.
2) The SPI protocol is shown in pag 33 and the 90333 can actually operate only as a slave. If the SS line is low, the 90333 will listen for a request from the master ( MOSI = Master Out Slave In) and the slave or 90333 will answer through MISO ( Master In Slave Out). The SPI protocol for 90333 uses 3 wires, so Mosi/Miso are is done through the same wire.
|
Q:
I need some detailled information about the last byte SUM of the frame of the mlx90333. In the datasheet, it said that it corresponds to 8 LSB of the sum of the transmitted bytes. Well, I'm testing it and it doesn't. Most time (Not all the time), it corresponds to this :
{(LX + LY + LZ)Mod256} - { [ (LX + LY + LZ) - {(LX + LY + LZ)Mod256} ] /256}
LX : LSByte(Xfield)
LY : LSByte(Yfield)
LZ : LSByte(Zfield)
|
A:
The checksum byte corresponds to:
(MX + LX + MY + LY + MZ + LZ) mod 256.
Where MX is the most sign. byte of the X component, and so forth.
It corresponds to the 8LSB of the sum of the transmitted bytes (6 in total).
|
Q:
Is it normal that I always have about 6% of errors among all the measurements. I'm checking the latest byte SUM with the formulate you gave me :
{(MX + LX + MY + LY + MZ + LZ) mod 256}.
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A:
There are never any checksum errors in my bench setup. Maybe there is a marginal timing in your communication?
|
Q:
Well, in the datasheet section Timing, 't1' corresponds to the minimum clock period witch is 6.9 µs for the Slow Mode. This means that the maximum clock frequency is about 145 KHz. The 6% of errors ,that I had, are with the frequency of 64 KHz (clock frequency), but when I try to increase the frequency I have a lot of errors.
Maybe, like you said, there is a marginal timing in my communication. I didn't find it yet. What I want to do is use the sensor with his maximum capacities. Could you tell me the best frequency of use?
|
A:
There are actually 2 important items that you need to check, to guarantee robust communications:
- Timings: The max CLK freq is 430 KHz ( high speed mode of 90333) or 145KHz ( low speed mode of 90333). But you should also respect timings t2, t6 and t7
- Application diagram: Check the application diagram, especially the present of the resistors R1,R2 , ... It is important that the signals at chip level are between Vss-Vdd. Especially check at the rising / falling edges of the signals with a scope.
|
Q:
I am using MLX90333 to measure little movements in XYZ space.
Before I realize a system with microcontroller to read XYZ values by SPI protocol, I would like to use PCT-04 system.
Is there an UI for 90333 like the one for 90316?
|
A:
Yes, there is a UI 90333 and PSF 90333. This should be available on the CD-PTC04 or the latest revision can be downloaded from http://softdist.melexis.com
Otherwise ask for an update of the CD from your local Melexis representative.
If you do not yet have access to the software server, then please send a small mail with the request for an account to your sales contact, together with your name, email address and company /application information.
|
Q:
Do you have available an evaluation board for the MLX90333?
|
A:
At the present time we do not have an evaluation board available for the MLX90333. One is in development and may be available in a few months. Please check back with us in June and we should be able to provide a date for availability.
|
Q:
I read in data sheet if the automatic gain control is activated the actual gain used can be read out. But in PTC04 software i didn't find a variable "gain" or "amplitude". I only found a field "Filedstrength" in RAM. I guess this would be something like sqrt(x*x+y*y+z*z) - right ? Can we use this field to check if sensor is in recommended working range 20mT-70mT ? In SPI mode there are flag bits defined for "field strength too high" - but i didn't get them set even with strong magnetic fields. Can this function be turned off ?
|
A:
The actual gain can indeed be read out through the RAM parameter "VirtGainByte" (Virtual Gain) and is a value between [ 0..41]
Field strength is the result of Bx, By and Bz and is used for the automatic gain adjustment. to keep the field strength constant. This value has no absolute meaning and therefore not suitable to check the working range since we try to adjust the gain to keep this value cst= 80-90% of max ADC value.
The only indication will be the virtual gain, but it is not corresponding to an absolute field value.
Field strength too high is triggered if the field strength value or radius is > 100% , which indicates a bad combination of strong magnet and wrong gain setting.
|
Q:
i checked the "VirtGainByte" but it is always 0.
I tested a "strong" SamariumCobald cylinder magnet d=10mm h=5 and tested an air gap between 20mm to 0mm and the VirtGainByte remains 0.
Our simulation of magnetic field strength found that there must be more than several 100mT at gap=0. At 1mm gap ~250mT, at 20mm ~4,5mT.
The 90333 has a working range 20mT-70mT so i expected that the AGC surely would be active in this range.
|
A:
The gain will only change if the automatic gain is actived, or not disabled.
Please check your eerpom setting "DisableGainCtrl = 0"
(see alo pag 12/13 of UI 90333)
|
Q:
the "DisableGainCtrl" wasn't checked.
I changed in the "EEPROM" Window with Read/Movetotemp/Program.
But sensor didn't recognized this.
Then i closed the ptc04 software and startet again and sensor showed change in VirtGainByte. Must the sensor be reset by restarting the PTC04 software if i change some EEPROM Variables like "DisableGainCtrl" ? Then it's clear.
|
A:
There is no need to restart the software PTC-04.
But after changing the EEPROM parameters of 90333, it is recommended to restart the device to guarantee the changes are valid and used in RAM.
In advanced you can HotReset the device or reset Vdd.
|
Q:
I was trying to work with MLX90333 triaxis 3D-Joystick Position Sensor.I want to calibrate it for degree measurement. I looked through the datasheet and found the expression to calculte the degree i.e. alpha & Beta. I was wondering about how to find Vz in the expression because the sensor has only two outputs Vx & Vy.
|
A:
The sensor does not have Vx and Vy outputs. The two outputs are the calculated Alpha and Beta angles. Vx, Vy, and Vz are only available through a special SPI mode.
|
Q:
I've question about MLX90333.
How can I program it(is PTC-04 the only option)? Is there any document how to do it ?
|
A:
Melexis programmable hall sensors can only be programmed with the PTC-04 ( no other option).
For more information regarding programming MLX90333, please check the CD PTC-04 / UI 90333.
|
Q:
I'm testing MLX90333 with PCT04 in SPI-XYZ mode.
I would like to know what XYZ hex values mean in distance units since Datasheet speaks only about Angles
|
A:
The XYZ values represent the magnetic field strength. They do not translate directly to distance.
|
Q:
I have obtained 3 mlx90333kdc (lotnr P21523x3x1) samples. The datasheet tell's me that there're 3 possible mode's,(analog, pwm, spi). I would like to use spi mode. It's not clear to me in what kind of mode the mlx90333kdc is, and how can I change this communication mode?.
|
A:
The devices are in Analog mode by default. You need a PTC-04 programmer to change the mode to PWM or SPI.
|
Q:
Tn datasheet of MLX90316 a parallel circuit RC is used at the output analog, but the parallel circuit RC does not act as a filter here.I want to knox what'is its role here.
Thank you for help
|
A:
The recommended application diagram in the datasheet exist out of 2 parts.
1) The min. required capacitor on the output pin of 90316. This is required for the stability of the analog output signal and for protection of the output.
2) The ECU is only an example. The pull down resistor (or pull up) is used to a definite a logic level if the MLX90316 is in diagnostic mode like broken Vss ( see pag 20).
|
Q:
Hi.
I'm one of many "old school" engineers who learned elecronics in the analog days. I'm employed by a company who builds automation equipment. I've used many analog sensors such as hall, pressure, strain gauge and others. I've always conditioned the analog signal with analog circuits which are very accurate and give me a very good result.
Of course, my younger colleages tell me I'm in the dark ages and programmable sensors are the new thing. Honestly, I believe them, but hate to admit digital electronics is over my head.
I keep seeing Melexis ads in magazines with "Simplifying Sensing". Maybe Melexis can teach this old dog some new tricks? Help?
|
A:
Does Melexis have any aplications notes where an analog solution is compared/replaced by a digital one?
|
Q:
Most capable analog engineers adapt pretty quickly to Melexis digital products. If you have specific axample of what you are trying to compare I am sure our applications and Field Applications engineers can provide a comparative study or assist in your setting up a bench test for your own comparison. A good example would be an analog Linear Hall IC. USe an example application note from allegro's A3506 or other analog Hall IC. Look at the example of a DC current sensor. With the analog part you need to adjust # of windings or external applifiers & trimmers to maintain an offset and gain arrangmeent that resuls in full output signal span depending on the input current sense range desired. using a Melexis 90251 it is a simple matter of reprogramming such characteristics to match each case.
For sensor signal conditioning the www.melexis.com website has many good application notes to help get you started. inaddition many evaluation boards and demo boards for specific roducts can help jump start your bench testing and trials. It would be helpful to know what you top priority is so that a specific product can be recomended as a first case study.
A good analogy is to think of replacing all those trimmers in your analog cicuits with digital bits controlled through a one time programming interface. It generally means you can more easily achieve the best performance even when your signal input varies from one unit to the next without a lot of "twiddling pots" and trial and error. Usually a process can be established to allow a PC to check the span, offset and thermal behavior , predict a set of digital compensation factors, prgram the sensor, then verify and iterate 1x or 2x until the desired performance is achieved.
|
Q:
Thanks for the info. I agree the evaluation kit is a good idea for an old dog like me. I also read a bit of info on Melexis's sensor interface, and even though there is alot of digital talk, it seems there is an analog input and an analog output, which is what I am used to dealing with. I think this "out of the box" eval kit might be just the "bridge" I need to get me across the technology gap. A similar exrcise can be done for a strain guage pressure sensor with the MLX90308 compared to a series of instrumentation amplifier cirucits that would correct for the non-linearities of the pressure transducer over span and also due to temperature.
|
Q:
|
Q:
whenever I press 'Finish program cycle' in 90333 user interface, device is programmed but then I cannot read/write it anymore. When I press 'New device' there is a message 'no valid response'. I cannot even read EEPROM or RAM (I get FF reads). Is it the normal beaviour? How can I try parameters settings before locking the device?
I don't push 'Memlock' or 'LOCK'.
|
A:
As long as you did not press the MEMLOCK button, the 90333 can be validated, reprogrammed, checking EEPROM and checking RAM.
Only if the SPI application mode was selected, the PTC-04 communication is sometimes more difficult to establish. Setting Vdd to 0 V first could help.
In all other cases I do not know any reason why you can not reprogram the device.
|
Q:
Setting Vdd to 0V first seems to have some benefits. I have a question: does this problem affect just PTC05 communication/programming or also the application environment?
|
A:
In the application ( Vdd= 4,5..5,5 V) the device will always be in SPI mode, so there is no problem.
If the device is programmed for SPI mode, then only entering into the PTC-04 communication mode ( Vdd= 7.5V) is sometimes more difficult. Once the device is in programming/communication mode, the communication is also no problem.
Therefore it can help to first switch off the device ( Vdd =0), or limit the time at Vdd=5V ( Tsynchro) or reset / hotreset the device a couple of times until it switch to PTC-04 mode.
|
Q:
I have a question about the qualification of the MLX90316. Is it AEC Q-100 qualified? If yes, for which grade?
|
A:
Yes, Melexis is a main supplier for the automotive market and MLX90316 is AEC Q-100 qualified ( with MSL 3 preconditioning)
|
Q:
Thanks for your answer, but I was not looking for the MSL level. I wanted to know the temperature grade. Was the product qualification done according grade 0 or grade 1 (-40°C to 135°C junction) or grade 2 (-40°C to 125°C)?
Thanks.
|
A:
MLX90316 is qualified up to 150 C , so grade 0
|
Q:
I have only simple question.What is the relation between Speed and Resolution ?
MLX90316 in SPI mode has 14 bit and Analog or PWM mode has 12 bit..
Want to know which has higher speed ??
Relation between resolution and accuracy is invers..like slow mode has higher accuracy then Faster mode (SPI) (Is it correct ??)
|
Q:
the frequency of the main clock of the MLX90316 is programmable. Two options are available: 7MHz (slow mode)or 20MHz (fast mode).
Depending on which mode is used the resolution of the ADC converter is reduced, i.e. if the slow mode is set, the resolution is 14 bits + sign, if the fast mode is set, the resolution is 13 bits + sign (as explained in the datasheet from April 07 on page 13/41).
Furthermore, some other parameters are also depending on the speed mode (see page 10/41 and 12/41 of the datasheet from April 07).
However, the resolution of the SPI output protocol is always 14 bits independently of the chosen speed mode. What is dependent, is the sampling rate (as explained in the datasheet from April 07, page 12/41).
|
Q:
WE ARE ANALYSING MELEXIS CHIPS FOR POSITION SENSING. I HAVE A QUESTION REGARDING RESOLUTION.
we programmed a transfer curve /|/|/ (3*120 degrees) PWM 800 Hz.Is it possible to have a resolution of 0,03 degrees with this curve.
|
A:
I assume that you are referring to the MLX90316.
The theoretical resolution for the PWM output will indeed be 120 deg / 12 bit , or 0.03 deg. But if you talk about the final resolution at the output, this is related the noise to signal ratio, then it will depend on the gain and filter setting.
When the field is strong enough and you can apply a strong filter, then this should be feasible.
|
Q:
Is the Hall Effect US1881KUA RoHS Compliant?
|
A:
The plating of the US1881KUA is pure matte tin, so therefor it is ROHS compliant.
More info:
Melexis Lead Free Statement
Melexis Lead Free (Green Packaging) FAQ
|
Q:
I need RoHS certifiction of Melexis PN US1881LUA
When available?
|
A:
This product is available in Lead Free package but the certificate is not available on our website. Please contact your local sales representative for this certificate.
|
A:
there is only general information about RoHS on our website: http://www.melexis.com/relinfofiles/lead_free_statement_may05_1.pdf
For Melexis, leadfree = ROHS-compliant.
Because in the ROHS-directive, there is mentioned a banned substances list: for Melexis only the lead must be banned from our products (all the other substances are not included in Melexis products).
So, if a product is leadfree, it's also ROHS-compliant and vice versa.
|
Q:
I'm testing this sensor(with a uP with A/D)and I have some troble when I sampling the signals from sensor.There are glitches like the S/H circuit of ADC is not working in right conditions.
My ADC has an input capacitance of 30pF (max) and its allowable signal source impedance is 5Kohm (max).
In 2dsa-10 datasheet there's no references for output impedance, only for output loading (1mA).
Oh, sorry, I forgot that the X/Y output of 2d-sa are connected directly to the ADC.
Do I need a buffer?
What is the output impedance of 2dsa-10?
|
A:
if you measure with a voltmeter the sensor outputs, do you have than correct signals?
|
Q:
.With a voltmeter I measure correct levels (because of voltmeter filtering I think).
Look at these acquisition:
Because this forum doesn't support html, just copy/paste these urls into your browser:
- ADC on
http://img432.imageshack.us/my.php?image=adcactivemk3.jpg
- ADC off
http://img255.imageshack.us/my.php?image=adcnopw1.jpg
|
Q:
2SA-10 can not give out frequencies over 20 kHz. Your peak has a higher frequency.
what is your DAQ frequency?
|
Q:
I'm sampling at 2.25KHz (8 times for average every sampling)
I'll try with a buffer.
|
Q:
I tried with a buffer (voltage follower) and I had the same results.
Look at this:
http://img131.imageshack.us/my.php?image=bufferoutputrt4.jpg
As you see every time I sample there's a spike in the signal.
I think that ADC of my uP is not suitable for this application.
I'll contact my uP vendor to solve this problem.
|
Q:
|
Q:
Please explain the major difference between single and two die package.I found that the difference is the quadrant angle,is it right?also,my application is to sense the position of the valve movement from 0deg to 90deg with the resolution of +/- 0.27deg.please suggest,which package i select for this?
|
A:
I imagine you refer to the MLX90316.
This part is available in SOIC-8 w/ a single die and in TSSOP-16 w/ 2 dies. This special construction features actually 2 dies which are galvanically isolated and it can therefore be considered as a "full redundant" solution when the final position sensor application requires such a level of redundancy (i.e. so-called "safety critical" applications e.g. pedal position sensor, throttle position sensor...)
To answer your specific question, you can either use the Single or the Dual: there is not any difference in the functionality other than the dual die is a redundant version.
|
Q:
I am setting the mlx90316 with PTC04 by the tool "Main auto-calibration screen". The IC is mlx90316kgo.
When clicking the "New device" and "Set settings" buttons, it is ok. But when click the "characterize" button, an error dialog turns out: "PTC-04 received from the chip ACK/ERR=80h while writing to address 0072h". What is the reason? Could you please tell me how to solve it?
|
A:
The error indicated that there is no readback / communication possible . Make sure the device is connected correctly to the PTC-04. Check the connections of Vdd, Gnd and output. This can be verified with measurements screen: VDD=5V, IDD = 6..12mA, Vout = 7-8%Vdd for un-programmed parts.
|
Q:
The measurements screen shows: VDD=5V, IDD = 7.7mA, Vout = 3.5%Vdd
What does that mean?
|
A:
The signal of the output ( die A ?) is too low which indicates that
a) it is not correctly connected
or
B) the device has been reprogrammed.
I advise to check the connection of the output pin.
Die A : pin 15 of 90316 must be connected to pin 2 of DB25 ( PTC-04).
Die B : pin 7 of 90316 must be connected to pin 9 of DB25 ( PTC-04).
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Q:
I would like to know if it is possible to programm the MLX90316 (let's say MLX90136KDC-) paramters via a generic on board microprocessor's SPI, without using a specific tool like the Melexis PTC04. This would allow an on board calibration.
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A:
Unfortunately the progamming is more complex than a SPI interface can manage. Hence the PTC04 is the programming tool required.
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Q:
I am designing FPGA as a Master for the 90316.
Spec page 29, 16.10 Frame Layer.
Couple of questions:
1) After Master will sent described 10 bytes should I tugle /SS to HI and LO to receive Slave 10 bytes (data), or may be Slave 10 bytes will come in the same Frame after Master's 10 bytes?
How the Master bytes separated from Slave bytes? MISO and MOSI is just one pin.
2)Bytes description of Data Frame is not the same as in the drawing:
Text: " Data frame consists of 10 bytes:
2 start bytes (AAh followed by FFh)
Drawing: " slave (MISO) 2 start byte are FFh.
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A:
1) No, /SS should remain LOW through the whole data frame. The 90316 uses the same pin for input and output (MOSI / MISO). If you use one FPGA pin for input and output, you must tri-state the data pin after sending the command AAFFh. The slave replies with the data over the same pin.
If you are using separate FPGA pins for MOSI and MISO, see the application circuit in figure 18 of the MLX90316 datasheet. The external FET combines the MOSI and MISO to a single pin for the 90316.
2) This is a common source of confusion; The diagram shows MISO as FFFFh to indicate that the 90316 output is at a high impedance when the master is sending the command.
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Q:
I get it.
One things regarding /SS signal. In your post you wrote that "/SS should remain High through the whole data frame". On the Datasheet (page 29)Timing diagram shows /SS goes and stays Low during the whole data frame. Could be a typo?
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A:
Thanks, I corrected my mistake in the previous answer.
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Q:
Thanks, going further into FPGA design I have couple more questions:
1)Each byte sent by 90316 (slave) must have 8 SCLKs from Master. Is that true for the first data byte too?
2)I am using only stright data 2 bytes (not inverted bytes) from 80316. May I shorten the frame by returning /SS High after reseiving those stright data 2 bytes ?
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A:
1)Yes, the master must send 8 clocks for each data byte
2) Yes, you can interrupt the frame at any time by returning /SS High.
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Q:
Thanks, regarding t5 (Max /SS HI) data sheet shows 300uS/1500 uS - ratio 5:1.
All other timing parametrs show ratio 3:1. Could be a misprint here?
May be it shall read 300uS/900uS ?
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A:
It is correct that t5_min is 1500us in low power mode.
/SS is sensed by polling, at a rate of about 1ms (vs 200us in high-speed mode).
Here comes the ratio 5:1.
Do you interface a single slave or several slaves?
In single slave, /SS high is only needed to resync slave vs master
in case of framing error.
If you cannot live with t5 = 1.5ms, you might try to keep /SS low
as long as the redundancy bytes do not show communication error.
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Q:
Thanks for info. One more question.
In the MLX90316 Spec Fig 16, SPI master (MOSI) has an open collector transistor with 1k pull-up, which meant HI level impedance is ~1k.
I am using FPGA, which during transmission provides much lower impedance when in HI state. Is that supposed to be a problem for the MLX90316.
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A:
The pin MOSI is bi-directional.
A high-level (the recessive level) is set by the external pull-ul resistor (1K).
A low-level (the dominant level) is set either by the Master (ideally through the external MOS transitor) or by the Slave, which is configured in open-drain mode.
This allows bi-directional communication.
You cannot connect directly the FPGA MOSI output directly to the MLX90316, unless the FPGA output is configured (like the MLX90316) in open-drain mode.
For a design more robust to EMC, I advice to implement the application diagram of Fig. 18.
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Q:
Can you give me cross for Honeywell's sensor SS49 series.
Will Melexis's 90242 will be a match for the same.
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A:
MLX90242LUA-CC03 is close to the SS49
- except the sensitivity is not the same ( MLX = 4mV/Gauus <-> Hon = 2.5 mV/Gauss)
- TC is 700 ppm for MLX and 1000 ppm for Hon.
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Q:
I was wondering is the CSA-1V would be useable in a low-power application. Is the start-up time characterized (5v applied till valid output?)
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A:
The current consumption of the CSA-1V is approximately 16mA. The sensor doesn't have a standby mode function or something similar. The start-up time is typ. 150us and max. 200us.
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Q:
if I look at figure 16 of the MLX90316 datasheet it seems the device or at least its SPI port is 3.3V compatible, even if the device works at 5.0V. Is this true? In other words I didn't find in the datasheet the Vil (V input Low) for the SPI port). Could you confirm I don't need to adapt the levels if a use a 3.3V microprocessor?
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A:
Indeed, the /SS , CLK and MOSI are 3.3 V compatible. See also table 3 on pag 34.
Vdd, however needs to be 5V +/- 10 %
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Q:
I want to apply the us1881 with the 60 magnet poles and 30 thousands circles per minute.I calculte the frequency is 30K Hz.May us1881 be used in the condition?
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Q:
The US1881 maximal switching frequency is determined by the response delay between triggering the Hall sensor above a magnetic threshold (Bop or Brp) and having the correct change on the output.
In such condition, the maximal switching frequency is 10KHz typically. It means that the US1881 is able to detect and give the correct output state in a magnetic field switching up to 10KHz typically.
The absolute maximal limit of the switching frequency is expected to be around 15KHz.
Hence, in the condition you mention with a magnetic field switching frequency at 30KHz, it is not possible to use the US1881.
However, according to your condition, I understand the rotor is composed of 60 different poles, so 30 north and 30 south poles. To calculate the magnetic field frequency, the following formula shoud be used :
Ffield = ( RPM * N ) / 60
Where:
Ffield is the frequency at the output (so the magnetic field frequency as well)
RPM is the rotation speed
N is the number of pole pairs
60 different magnetic poles means 30 pole-pairs.
In case the motor rotates at 30000 RPM, the magnetic field frequency would be 30000 * 30 / 60 = 15kHz.
In such condition, it might work but it is close to the upper limit so it would be advised to reduce the number of magnetic poles to reach 10kHz switching magnetic field.
By reversing the above formula, we can conclude that a rotor composed by 20 pole-pairs is safer.
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Q:
Pls help me solve a question:How much hz is the us1881 switch frequency.The clear answer can't be found in the datasheet.
One another question,Do you have the hall element adapting to the 100KHz frequency application?
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A:
No, we do not have such product. And to be clear any manufacturer who claims 100Khz in a plastic package device is choosing to ignore the eddy current effects on magnetic fields caused by the copper alloy leadframe. The leadframe itself will limit the frequency response to less than 30Khz. Even a fully analog IC will not work as you might think and as the datasheet claims, at 100Khz. As a practical matter most Hall switch or latch devices require fairly large fields to switch and getting fields this large to change state at frequencies above 30Khz is challenging.
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Q:
Can you finish explaining the formula:
Ffield = ( RPM * N ) / 60
Where ...?
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Q:
hello, I'm new to using this hall effect IC. I was hoping to use it to see if there is current flowing through a PCB trace (I had thought to lay the TO92 body at the required angle to the current flow on the trace). was this a foolish idea? cause it doesn't seem to act as I expect.. thoug it could be that I'm not providing enough current for it to read. which would also be a dead end maker..
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A:
As you have surmised correctly this is not an appropriate use for this IC. The current in a PCB trace is generally much too small and generates a very weak magnetic field. Usually the field is orders of magnitude smaller than the field required to switch an 1881 Hall Latch. Even our linear Hall ICs, like the MLX90215 or MLX90251 are not sensitive enough for this task. Melexis has a device called the CSA1V that can be used to detect certain currents flowing in a PCB trace. You can learn more about this part at http://www.sentron.ch/csa.htm. Sentron is a Melexis company that specialies in advanced magnetic sensor technologies.
To make the US1881 work would require a toroidal ferrite core with the 1881 inserted into an air gap in the core and then likely several hundred turns of copper magnet wire on the core. The current would then be run through this coil and the field in the gap would be a multiple of the amp turns of the windings. I am sure this is not what you had in mind so look at the CSA1V and see if it could meet your expectations. This IC uses very clever on chip flux concentrator technology to give a more sensitive detection solution without requiring ferrite cores and windings.
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Q:
Dear Sir Or Madam
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Q:
Can I use US2881 to detect if an equipment is ON (drawing current < 1A max 20A). At 1 A and 0.1"" away the flux is only 0.8G or 0.08mT. Are there any low cost off the shelf toroids or anything else that would increase the flux? I am guessing I would need 4mT and the output would be switching at line frequency (50/60 Hz), right?
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A:
You can't make a "clamp-on" current sensor with this technique.
You need at least 15 turns to produce +/-9mT at 1 amp in a gapped toroid (using the approximation B = 0.6mT / A * N). The output will switch at line frequency.
I don't know any manufacturer that sells toroid cores that already have a gap for the hall sensor.
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Q:
Will it be possible to use the US4881 hall effect switch to sense the magnetic field surrounding a spark plug wire? I want to try using to sense the electical pulses when the spark plug (high side of ignition coil) fires (discharges)
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A:
No this Hall IC needs DC magnetic fields of a substantially larger magnitude. The electromagnetic field around a plug wire is both too weak and too fast to reach the gauss levels needed to reliably actuate this IC. Typically an inductive type current transformer and a detection circuit are used to capture this signal. The Hall sensor idea is not suitable.
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Q:
From looking at the datasheet for the US5781-L-(UA/SE), the actual "Hall Cell" inside the chip appears to be a different size depending on if the chip is the through-hole or surface mount version(may not be drawn to scale). If so, does this affect its sensitivity?
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A:
The Hall element of the US5781 is the same size in UA and SE package. As you correctly concluded the drawings are not to scale.
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Q:
I am using a US5881 Unipolar Hall Effect Sensor and a 10k pull up from Output to Vdd (+5V). This typically works well, however we have had a few that required a lower value resistor value. Is there a recommended pull up value that should be used?
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A:
The value of the pull-up resistor is limited only from the lower side - the output current should not to exceed the Absolute Maximum Rating (for US5881 it is 50mA ). The upper limit , if exists, comes from the application ( particularly the load resistance and capacitance). The pull-up together with the load resistance form a resistive divider which defines the HIGH logic level. This level should be appropriate to trigger the load.
Example: If Rload=Rpull-up , then HIGH logic level is equal to VDD/2 .
Be aware that the load capacitance together with the pull-up resistor influence the output rise and fall times. If you need a faster response decrease the value of the pull-up.
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Q:
We suffered a big problem about applicating the IC US72.
We used it in our brushless motor.
During test we find the motor's startup voltage has big variation. For example, at the same test condition, we supply a motor with 8V, it can be started up sometime, while can not be started up some time.We test the internal resistance of the motors and find it is well consistent.
Could you give me some suggestion about this problem?
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A:
The motor start-up voltage variation you experienced may have different explanations.
It could be due to dead point, mechanical friction, rotor mass, Hall sensor position or else.
Is it possible to provide more information about the application and schematics ?
Do you observe such variation (start or no start at 8V) with one and the same motor or between several ?
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Q:
One question:
1. Topic: The issue for US79 of application.
2. Major issue: US79 can be used to 48V's opearting Voltage?
3. Application Model:
- DC Fan Size: 0515( 5cm* 5cm)
- Opearting Voltage: 48Vdc.
- Continue Current: 250mA.
- Lock Current: 300mA.
4.Action: According to US79's Applications Information,it's suitable for the project if I add components like Resistance.
Thank you very much for your attention, and looking forward to see you early reply soon.
SKYMAN
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A:
Supply voltage of 48V is far beyond the maximum specified operating limit for this chip. It is not recommended to use this product at so high supply voltages without a special overvoltage protection.
In the product datasheet there is not available information for so high voltage application, but for higher output current option.
If you write to kka@melexis.com we will try to support in your application.
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Q:
We are using a dc blower with frequency sensing that works with the US90 fan driver. Apparently, this fan cannot handle a (high side) PWM drive signal at the power supply line. The same fan type without the frequency sensor uses the BA6817 driver from ROHM and works fine with PWM drive.
My question is: can the US90 handle a PWM drive signal at all(maybe the no-Vdd feature makes it difficult)? If so, is there any info on allowable frequency ranges, duty cycles, startup conditions,... ?
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A:
Thanks for your enquiry.
The PWM speed control scheme is possible with the US90. However, you need to adapt the application depending on the driving you want to achieve.
Could you please give some more information about:
- application schematics ?
- PWM frequency and duty cycle limits ?
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Q:
I have ordred the programming set for the 90316, but I need the name of company where I can buy some diametrical magnetized magnets. I have searched everywhere, without any luck, here in Denmark...
Nicolai Madsen - Denmark
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A:
Here is a list of possible suppliers:
(alfabetic order)
AS-Elektronic :www.as-electronic.info
Bomatec :www.bomatec.ch
Kane Magnetic: www.kanemagnetic.com
Magnequench: www.magnequench.com
Magnetfabrik Bonn: www.magnetfabrik.de
Magnetfabrik Schramberg: www.magnete.de
Precision Magnetics: www.precisionmagnetics.com
Sura Magnets: www.sura.se
or magnetweb.com
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Q:
Sir,please explain the zero/initial position programming in MLX90316.
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A:
The MLX90316 is typically programmed in the final application (through supply and output pins using a dedicated programming tool called PTC-04).
The transfer characteristic i.e. Output signal (either analog voltage, PWM duty cycle, SPI) vs. Angular position (in degrees) is fully configurable (see datasheet).
To proceed, you need first to mount the IC into the application facing the magnet (diametrally magnetized and located onto the throttle shaft).
Then you drive the application towards both mechanical stops or any other target positions. In those positions, you calibrate the transfer characteristic according to your output requirements (offset, slope,...)
You can also acquire MLX90316 which has been preprogrammed but this actually is only worth for 360 degrees application. In such a case, you get a 0.5V to 4.5V output characteristic for 0 ... 360 Degrees.
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