CPU 315-2DP SF Fault

Hello friends

I've a system of S7-300 with two levels of networking , the main network consists of 4 CPU's S7 315-2DP through communication module CP 342-5

one of the three CPU's goes to STOP mode with SF LED ON ( RED ) and then the CP 342-5 also goes to STOP but the others still RUN

this unit has local network through MPI port using PROFIBUS cable to distributed I/O system with PROFIBUS communication module 6SE7 151-1AA02-0AB0 and attatched I/O modules

this happens ( RANDOME ) the system may work for days and some times it can't work , when restarting the system , it starts again and RUN

If there is any thing to check or to monitor , please I need your help

Hassan Shahat

Dear friends

Thanks very much for your great help

I checked the diagonistic of the CPU , there was something about rack , I changed rack and communication module CP 342-5 also checking and adjusting the connections to the module , but still having the error , but there is something new ; that the CPU continues running even the module CP 342-5 is stopped and not communicating , when trying to check the module through the CPU , it is out of communication ( Old and new modules with old and new Racks )

Many thanks in advance for your great help

hi
Attachthe diagnostic buffer information on forum???????

regards

Dear Sir

Thanks for your help , please find attatched the diagonistic files for both CPU-315 2DP ( diagonistic1 ) and CP 342-5 ( diagonistic2 ) and also picture for both screens

Waiting for your help

Best regards

Hassan

Dear friends

I loaded the OB's 86 and 87 ( Rack and Comm. fault ) , now the system is running , no stop happened , the problem seems to happen momently as rack fault , but as I said before I changed the rack and the communication module !!

I don't find any considerable reason for that ???

Any way many thanks and best regards