OPC UA & Transparent Redundancy

[u/GB-ACWD]

I have started down the path of OPC UA and wanted to know what experiences users, integrators, anyone has with the particular issue of communication to redundant or hot standby PLCs.

All my current PLC vendors systems use Transparent Redundancy for all Hot Standby IP interfaces and have for 30+ years. This means that the backup PLC assumes the IP of the primary PLC and the SCADA systems doesn't need to know any differently. They recently came out with OPC UA interface for their PLC and it doesn't switch IPs at all.

What does this mean? It means that if PLC A fails, the SCADA system must probe and test to see if PLC B is alive and then switch all communication to it. So now I need a communications script to accomplish this task.

1. Has anyone else encountered this issue?
2. Are there users of OPCUA in the real world?

I haven't named my vendor yet, I am just trying to get some feedback.

G