S7-400 Industrial ethernet

Hi all,

I have been having communication error on s7-400 industrial ethernet. 3 PLC's have been communication with each other on industrial ethernet till date. The Panel was switched off for maintenance, for eg. PLC1, PLC2, PLC3

PLC1 & PLC2 - no data transfer
PLC1 & PLC3 - data transfer successful
PLC3 & PLC2 - data transfer successful
The logic has been working till date, since the panel was switched on, no data transfer.

I have checked the communication block, the send and receive i get no error and i see job status 8181H.

pls help.

Thanks

Investigate the diagnostics buffer of all CP443-1 modules.
Make a complete listing of all hardware and what communication that is setup.