MMS Connect supervision Error 421, Communication Watchdog failure
In our plant we have the ABB 800XA DCS system.
I received an alarm:"MMS Connect supervision Error 421, Communication Watchdog failure" (see attatched file). After this alarm was received i cannot see or operate certain motors and valves of the plant.
I checked for failure alarms on the PLCs (PM861A)and communication modules (CI867, CI853, CI854 etc), ethernet cables etc. I could not find any problem there.
I also checked with the Plant Engineering Workstation (Service structure) to see if some service stopped but all services were up and running ok.
I would be gratefoul if anyone could give some help to solve this problem.
The provided information seems to be incomplete.
MMS communication usually is used to exchange a variables between AC800M controllers. Without to know details of your configuration, check the connection between nodes 192.168.121.1 and 192.168.121.2 or the connection to this units and your PLC