Watlow MLS - Manual (Page 47)

Installation
MLS User’s Guide 35
AIM Communications Failure
The controller continuously checks communications between the MLS-
PM and the AIM. If communication stops for more than five seconds,
the MLS-PM display indicates AIM COMM FAIL, the PID mode
changes to manual, and the controller sets every output to the output
override percentage.
WARNING
PID outputs remain in manual mode after an AIM
communications failure. After an AIM failure,
change the PID control status back to automatic
mode for each control loop.
An AIM communications failure also activates the global alarm output.
If you have selected a digital output from the Global Parameters menu,
an AIM communications failure also activates the output.