I have an application where a field PLC controls 2 pumps and a blower with various other IO hardwired to it. There’s another PLC that is solely the HMI/SCADA PLC. Both are Groov Epics with the newest firmware. The HMI PLC has ignition edge 8 for its edge gateway scripting capability. The field PLC has the non ignition firmware. The HMI PLC fetches values in Groov view directly from the field PLC via OPCUA. Both PLCs run Codesys.
Here’s the problem - intermittently, maybe once a day(sometimes more), communication is lost between the field PLC and the HMI PLC. Attached is a screenshot of it. I actually experienced it first hand a few times where I was kicked offline while online in Codesys(of the HMI PLC) due to communication failure or something like that. The communication to the field PLC was also lost. Anywhere between 2-10 minutes will go by before comms are established again.
The even bigger problem - somehow even though all of the control is local, that comms loss kicks the blower off and sometimes faults it. Still not sure why, but it’s been proven to directly correlate with the comms failures. Not sure if it has something to do with the set points from the SCADA screen not talking anymore(shouldn’t be since the set point variables are persistent in Codesys). I was hoping updating to the latest firmware would address the issue since it seems like that was an issue before, but it has not(maybe it’s gotten a bit better).
Really need help on this one!!! Any thoughts?
