For our steam turbine control we are using S7-300 PLC with WinCC SCADA. Since a few days we face a very strange problem in this system. We found some motors are not operating from the SCADA graphic page. Later we found out that these same motors are operating when we changeover the PLC CPU. We have redundancy for CPU 315-2DP and for the interface modules. By changeover I mean is that when we switch over to CPU no. 2 from no. 1.

We have checked thoroughly the program residing in both the CPUs and found exactly identical. The netwoking with the SCADA is by MPI port and networking of peripherals is by PROFIBUS.

Can anybody out there give some hints for trouble shooting this problem? Thanks.

 

Find out the MPi address of the CPU1 and CPU2. In case of failure of one CPU,STOP winCC runtime. Then u got to change the MPI address in the WinCC and then start runtime of WinCC again.

This is one way of solving ur issue.

 

This problem is not an Addressing one, because the system works properly good, but failure occured early...

The main problem in this case could be found in communication ports (connection). This should be checked (MPI or ProfiBUS Connectors).

If the hardware is completely OK, then you should check the ALARM & LOGs in WINCC this is a easy way to find problems, then try to re-install S7-Protocols Driver in Wincc if problems exist.