Hello,
after two years of trouble-free operation, the PMT50 power panel exhibited a strange behavior once. The OPCUAConnectionOK channel remains TRUE, but all other channels are inactive. There is no diagnostic information indicating a problem, yet values such as temperatures and ModuleID drop to zero.
The only way to restore communication is to reboot the device; there appears to be no other method to restart the communication.
The panel acts as an OPC UA server, while the PLC reads from and writes to the channels as a client. An application OPC UA connection is also established, but it exhibits the same behavior—method calls end with an error.
Has anybody experienced this behavior before?
Does anybody know whether the node quality or node error ID is evaluated? If so, then OPCUAConnectionOK should not be considered TRUE in this situation.
When OPCUAConnectionOK = True, the server is started, and UA communication with the server works.
More information about errors on the UA interface can be found in the Communication logbook. I would expect something like a subscription error or something similar.
Hi Jaroslav,
the problem is that I need to detect a channel malfunction (e.g., poor node quality or a node error) in my application, and there is no diagnostic tool available except checking it in parallel through an my OPC client application subscription.
Once the problem is detected, I need a way to restart the connection automatically. However, all of the required functionality appears to be internal.
Yes, I can restart the communication manually by switching it OFF and ON again, but that is not a real solution.
I need a way to detect the problem and recover from it automatically.
Hi Corne,I forgot to mention that the logger does not show any misbehavior. I have attached the connectivity log.
The problem was detected on 23/06/2026 at around 14:30, but I don’t know when it actually started. Afterwards, I connected via Site Manager and tried to restart it at around 17:45.
The Connectivity log shows 14 OPC UA connection lost (3 on today) and 3 OPC UA connection failed errors.
I can’t correlate yet why these errors are coming.
Could you supply all logbooks, so that there is more information available like downloads or warmstarts?
Otherwise I would expect external influences like bad cable, emc-problems.
Is the PMT50 directly conneced to the PLC or is there a switch or hub used?
Is the PLC a X90 cpu?