ADS1115 2 Channel module Interface and Programming

The module uses a 4.99Ohm resistor for the load of the 4-20mA interface (Using the INA196 chip):

  • 4.99ohm @ 20mA gives a full scale of just under 0.1V
  • The device resources tab recommends using the Arduino ADS1115 interface library.
  • With a gain setting of 2 the Arduino code comment states : +/-2.048V range = Gain 2.
  • The description tab for the device states that with a gain setting of 2 “at 20mA the raw ADC value will be around 32154”. This is not possible at an input voltage of 0.1V.

Can anyone clarify what is incorrect?

ADS1115 doesnt read the voltage across the 4.99Ohm resistor. there is an on board amplifier which reads the 4-20mA input and interfaces with to the ADS1115.