Dears,

I have PLC S7-300  and sometimes it go to stop mode and diagnostic buffer at each time show different address of failure station, Bus 1 addresses (sometimes address 10 or 13 appear) and Bus 2 addresses (sometimes address 31, 15 appear).

Note :CPU has two buses as shown in attached picture and fault may appear on any bus with no BF indication lamp on any bus station.

please support
Thanks

Hello,

pls attach here diagnostic buffer (file) of CPU.

As shown in your Picture, there are some movable cabinets and trailing cable.

So there is also a big chance of wirebreak in some bus- or power cable.

In this case, a diagnostic repeater may be very helpfull  to find the location of problem ...