Channel Malfunctioning

Please look in THESE, if you do not find a solution, come back with some feedback.

It isn't clear whether the dropping resistor is external or internal, but note that the input resistor value is/should be 250 ohms. A 250 ohm resistor provides a 1.00 to 5.00Vdc IR drop at the AI input for a 4-20mA signal.

If the input resistor is a 230 ohm resistor for 4-20mA, the voltage range the AI input will "see" is offset low and spanned low: 0.92 to 4.60 Vdc. A 12mA signal would be 3.00Vdc for a 250ohm resistor, but only 2.76Vdc for a 230 ohm resistor, resulting in 'always low values' if a 230 ohm resistor were used. This does not sound like your problem "giving some value that would add to the actual value". A 230 ohm resistor would provide a value less than, not greater than the expected value.

230 ohms is the minimum required resistance for a HART FSK signal to be developed on the 4-20mA DC signal.

The document only mentions a couple of LEDs for faults.

To check the resistance, do so when the module is not powered.