Trouble reading value from PR33-8. (4-20ma)

Hi, I have a PR33-8 8 2-Channel 4-20 mA Current Loop Receiver 16-Bit ADS1115 I2C Mini Module) and we are trying to read the AD-value using python example code on raspberry pi.

The readings is not as expected. The sensor is a draw wire sensor

The sample code refers to PR1-43. Is the any need to modify the code to make it work?

Update: I measured the voltage and it was only 4,64 VDC (G-IN1)


Both boards utilize the ADS1115 so the sample code will work for either product. However PR1-43 is just a raw ADC input board, PR33-8 on the other hand is a 4-20 ma input board which means it has additional electronics on board prior to the ADC inputs on the ADS1115. The raw ADC readings will need to be converted into a real world 4-20mA reading. However if you vary the 4-20mA signal applied to the input you should be able to see the ADC reading on the ADS1115 change. Generally what I do in an application like this is apply a low known value signal to the input, take a reading, then apply a high known signal to the input and take another reading. This tells you how the ADC value changes given a variable input and you can begin writing the math to convert the readings.


I would say that the problem was related to low output voltage. I modified the card so I could power it externally and then it works.