DP Station failure

I've got a problem with an installation automated with a 317 cpu. There are 4 DP-stations, 3, 4, 11 and 20. 20 is an SEW Movidrive, the others are ET200M. Station nr.3 or nr3 and nr.4 sometimes fail. The failuredoesn't last longer than about 2seconds. I'd like to knowwhat happens, is it a module that fails or is there a problem with the power supply. Is there a way to find out at all, and if yes, what is that way?
I have included the text from the diagnosebuffer, maybe it 'll help.

Hello,

HansJ is right. It is hard to determine what is the cause of the problem without knowing how the system looks like. What is configured and how.

Such Problems are usually the best cause for a Service on site. Al the surrounding issues can be checked at best if you are right in front of the System.

Best regards

J_Bell

well, I understand your point a bit better now.

The Problem is that the IM 153, as the Head-Module of the ET200M, has not storage on itself, so It can not store a kind of history for faults or something like this. The strange thing in your configuration is that the Slave#11 never fails, even so it isbehind the failing Slaves.This still leads me to the idea that something with the wiring or grounding is not right.
What you can do is the following, take a Laptop with CP 5512 and Amprolizer Software on it, install it at best at the Slave #3 or #4.Let the system run until you get another configuration Request Telegram for your Slave #3 or #4. You should havestored the information’s before and after that point, than you know what the Slave sees.This can tell you if the Slave is faulty, because the Data it received is right but it did not respond, or the Slave does not see anything. At this point you have to start to investigate where the Problem starts. If someone could stay overnight checking what is going on in and around the building... I can tell the strangest things can be responsible... trust me.

Best regards