Calibration data

[Zdeno5]

I have some weird temperatures and alpha parameters. What can i make with it? Some fixed alpha data or...? With the example data it works fine. I have 2 sensors and the data are same. The image is measured on smooth homogen surface at 25°C.

[slavysis]

Could you log the EEPROM, the parameters you have calculated, the frame data and the calculated temperature. Some sort of csv file format would be very much appreciated :).

Best regards

[Zdeno5]

https://github.com/Zdeno5/MLX90640/blob/master/DATA.csv

[slavysis]

I can't find the EEPROM data that you read from the device. Could you please share it as well.

Best regards

[Zdeno5]

https://github.com/Zdeno5/MLX90640/blob/master/EEPROM.csv

[slavysis]

Could you please check the performance if you use continuous mode? In step mode the calibration applies only to certain conditions and you may observe some strange values.

Best regards

[Zdeno5]

https://github.com/Zdeno5/MLX90640/blob/master/Continousmode.csv

In continuous mode are strange values too. Is it possible to get data like this?

[slavysis]

Well, that is strange. Could you please try with the default configuration - 0x1901.

Best regards

[Zdeno5]

It works with 0x1901. How can i get it work with 2 subpages? I used 0x1A0F, but it gives strange values.

[slavysis]

The device works with two sub-pages by default. It is alternating the sub-pages automatically (unless programmed not to do so). You need to have the 4 LSBs to b'0001' in order to have alternating sub-pages (0x1901 does that). I would say if you need to,you should only change the refresh rate and/or the resolution. All the other bits would be better to remain at the default values. Other wise you might configure the devices to work in some special mode that generates what you call 'strange values'.

Best regards

[pronot]

I also got strange values for Ta (over 600C for room temperature). When i write 0x1901 to 0x800D register as suggested, i get around Ta=30C for room temperature. But the configuration change is not permanent. Each time, i do power reset i have to write 0x1901 again. Is this the normal operation mode? If so, how can i make it permanent?

[slavysis]

The driver is not writing the configuration in the EEPROM. So if your configuration differs from the one in the EEPROM, you would need to set it every time after POR. Normally, 0x1901 should be the default value in the EEPROM also. Could you please send me a dump of the EEPROM?

[pronot]

When i read EEPROM register from my MCU with:

status = MLX90640_I2CRead(MLX90640_I2C_ADR, 0x240C, 1, &value);

i read the value as 0x1100

Also with the MLX90640-41 Eval Board, i see 650C for room temperature on the Windows software of the board (image below). EEPROM data may be garbled somehow?

I exported EEPROM data from MLX90640-41 Eval Board software also.

mlx90640-eeprom-export.log

[slavysis]

It seems like only the configuration value in the EEPROM is corrupted. So, if you just include in your code after POR a line to set 1901 in the register, the sensor should be working just fine.

[Heni13]

Hello , I have a problem dealing with my MLX90640-41 Eval Board : when using the software the Mesure was blocked between two images and the mesurements are false it ca be the configuration . How can i solve this problem? what is the function or the code line that i can put in the console to have the best configuration ? or can i reload a program into the stm32 chip in the eval board to reinitialise the board and have significant mesure. Thank you

[slavysis]

As you are using the MLX90640 eval board, could you please contact Melexis sales explaining your issue. I guess it would be useful for them if you can already attach some data - EEPROM dumps, settings and how you configured/used the eval board.

Best regards

[Heni13]

I am asking if someone knows how we can code the console of the MLX90640 Eval Board or where i can find the commands of this console

[Heni13]

good morning, i found the MLX90640 library :
MLX90640_API.cpp MLX90640_API.h MLX90640_I2C_Driver.cpp MLX90640_SWI2C_Driver.cpp MLX90640_I2C_Driver.h but in the drivers there is #include"mbed.h" and i didn't find this header file can you help me thank you.

[slavysis]

The I2C driver is platform specific. As MBED is one of the widely used platforms, the published driver uses mbed.h and all related mbed specific IO functions. If you are using a different platform you would have to change the I2C driver accordingly so that it ensures proper communication with the MLX90640 device. This would most likely mean you will also have to use the proper header files for the platform (MCU) you are using

Best regards

[Heni13]

I m using STM32f746zg . so i should change the i2c driver ? thank you

[slavysis]

Yes, you will have to change the I2C driver accordingly. Please note that the function parameters and result should remain the same and only the IO operations and library usage should be different.

Best regards