Thanks a ton, ASF.
I figured it wasn't internet of things but it's all i could think of...
Your logic diagram clears things up.
Some tips for working with Produced/Consumed Tags....
1. Create a UDT of the data you want to P/C. Make the first element of the UDT "Connection_Status", of Data-Type CONNECTION_STATUS (it already exists). That element contains 2 BOOL flags that consumers can monitor to ensure the consumed data is valid, i.e. the connection is OK, and the remote Producer is in Run Mode.
2. Copy/Paste that UDT to the Consumer(s), so that you guarantee they are the same structure.
3. Create your Produced and Consumed tags of that UDT, and I like to keep the tag names the same as well. You don't have to, but I see it as a "Data-Link" between the controllers, so I think it should have the same tag-name, e.g. "PLC1_Data" (Produced in PLC1), and "PLC1_Data" (Consumed in PLC2, 3, 4, etc.).
4. Set the number of Consumers correctly, it reduces network traffic to the minimum needed.
5. Choose your RPI sympathetically to the data you are transferring. If it doen't need to go at 20mS intervals, set it upwards to reduce network again.
HTH