Read 4-20 mA Sensor output using Colibri carrier board with i.MX7D SOM

We are using Colibri carrier board with i.MX7D processor. We want to read 4-20mA output from a sensor.
How to connect the 4-20mA sensor to Colibri Carrier board.
How to read the sensor output using this carrier board.

The imx7d has analog input pins 2,4,6 and 8
I have never looked the software side of the ADC in Linux.
But if you place a 90ohm resistor across your current output pins you would generate a max of 1.8V @ 20mA.

If you ground the negative pin and connect the positive pin to 2,4,6, or 8, then in theory the rest is just software config of your Linux.

Hi @eoin_oc

Thanks for your Input.
@Bhaskar, did you test this on your side?

Best regards,
Jaski

We have a pH sensor which provides 4-20 mA signal based on the pH value. We are plannning to use the above analog input pins to detect the current mA variation. If there are any samples to detect the signals coming out of above analog pins that would be helpful.

Not yet. Not sure is there any call back or API available to follow up on the analog input changes.

Hi Bhaskar,

You can refer below link for more information regarding reading ADC channel

https://developer.toradex.com/knowledge-base/adc-linux#Colibri_iMX7

It is as simple as reading a file in Linux.

If you quickly want to test, below command in terminal will give you raw value as for voltage applied on channel one

cat /sys/bus/iio/devices/iio:device0/in_voltage0_raw

Let me know if you still have any queries.

Best Regards

Ritesh Kumar