Modbus TCP, communication occasionally/often fails
I have Modbus TCP communication between AC800-PM865 (CI867) and 8 PLCs (AC500). Communication fails in non-periodic intervals (e.g. with PLC1 communication is good for a 10min, then it breaks, then is good for 5 min, then it breaks; e.g. with PLC2 communication is good for 30min then it breaks, then is good for 20 min, then it breaks etc.) It is the same for all PLCs.
I made various combination in ModbusTCP-CI867 settings but nothing came good.
If someone had similiar problem, please share a solution.
Voted best answer
not similar problem but one consideration/question to better understand: you've always had the same problem since you start with the communication from AC800 to AC500 or this problem occours for a short time?
Do you use UTP/STP cable and the lenght of the cable? Task for the communication?
It is possible that you have some disease resulting from the route/laying of the cables?
The speed of the communication?
IMHO, as you wrote it would seem that the problem was random and originating from causes external to the pure configuration of your system.
I had a similar problem. Problem caused CPU parallel connection managed. How to call this block.
1-Calling time will be extend.
2-Your connection slave so master limit 8 slave 64(I remember).So this is not goes to fault.
3-You can try all one, one paralell connection you polled one cpu and then close this polling and pass next cpu. (I think solve the problem)
4-Connection and receive time will be adjust.(I do not think problem here)