Most likely the mA output is not set to control output S1 and the controller mode selected to MAN. If the mA output is not directly controlling the chemical dosing, assign the mA output to the respective measuring parameter of interest (i.e. ppm, pH, etc.)or switch it off.
Note: Confirm that the controller mode is not on "HOLD", which turns off all instrument outputs including the mA outputs.
To test the mA output:
- Set the mode to MAN
- Main menu > IN/OUT > TEST, set the mA output to 6mA
- Measure the mA output signal at the terminals if the connected PLC does not show the value