error finding

hello
i have a problem recently occur in one of the nodes in our plc network there are SF on all modules and in interface module as follow,3x(SF&BF),1X(BF),3X fast(SF&BF),1X(SF),3X(BF)i change the interface module and also terminator module but the problem still exist it seems to be an hardware failure but which one? please help me to solve this problem.(6es7151-1aa05-0ab0)
thanks a lot for any help

Is the bus master cpu running?

hi
yes everything is ok system is running and it's not a bus fault

hi there
fortunately i solved the problem, one of DI modules was out of order.
have a nice day