Hi,

I  have a safety PLC with ET200s safety racks in profibus. My problem is that every 3 or 4 hours I have a sudden fault of all safety cards in the rack simultaneously, so I need to acknowledge the fault in order to restart the cards. As this cards are part of emergency system, all machines are stopped.

Any idea what could cause this simultaneous fault?

I watched in the diagnostics but I didn't have any cue of what it could be. I don't see any profibus error. I attach screenshot of HW config.

B.R.

Hello 

I think you are getting a stop mode on PLC some times

That is happened because the Maximum Cycle time of your Safety Run Time is less your Needs of Safety Cycle.

you should change the Max cycle time of Safety Run group 

Hi. Thanks for your reply.

I attach the diagnostics of PLC and comunication card. Maybe you can see many other faults in diagnostics related to some HW parts that are not connected yet.

The PLC did not go to stop during this fault.

I hope that help.

B.R.

Leandro

The current Max time in Safety group is 200ms. The CPU is not going to stop. I was thinking maybe the problem is with the monitoring time of ET200s is 150ms??(see picture)

As we have 2 CPUs in the same rack, if any of them goes to stop, the other also goes to stop.

B.R.

Hi.

I am thinking the fault could be relatedto the profibus. Look at this diagnostic after profibus fault.

B.R.