I want to know the process parameters and other IO status in S7-400R Redundant PLC System when there is changeover of CPU due to failure of one of the CPU of communication sub system?

We have been proposed with a configuration of Siemens S7-400R PLC with Redundant CPUs, Redundant I/O Bus (Profibus DP) and Redundant IM modules. I want to know in case of any CPU or IM module failure, what will be the status of the following:

a) Closed loop control status including SV and MV
b) Start/Stop and valve On/off commands
c) Any forced Digital inputs or outputs

Whether the CPU changeover will be seamless without affecting the process or plant to trip ?

 

As far as I know there is no such thing as an S7-400R. Redundant operation is possible with S7-414-4H and S7-417-4H controllers. In this case the controllers are continously synchronised with 2 high speed fibre optic connections. In case the master CPU fails, the backup CPU takes over seamlessly, as they are synchronised, no difference in program execution or in any of the outputs will result.

Forced inputs are allways forced for both controllers because they are synchronised, there will be no difference. If redundant communication is configured in Netpro with CP1613 and S7-REDCONNECT on the WinCC servers, no influence on the Operator stations will occur.