Dear Experts,

For a safety system I am using a S7-1500F CPU with ET200SP safety IO modules. The communication module for ET200SP is the IM 155-6 PN/2 HF. 

Issue:

When I unplug one of ethernet cable from IM 155-6 PN/2 HF, then all safety IO cards goes to fault and is necessary to have a global ack in order to became healthy again. As a result the plant is in ESD in a ethernet cable is unplugged. 

So please advice how to by pass this. I would like in this case (an ethernet cable is unplug) the IO cards remain healthy.

Thanks in advanced.

Please find the network topology. With yellow the lines that cause fault in ESD-IO.

Please don’t  downgrade the subject. No one force you to give a replay.