Hello,

recently I got a communication alarm in the machine and this alarm can be reset but will take place by chance.

There are OB 86 and OB122 in the program.

The messages in the  diagnostic buffer of CPU are:

[snip]

Hi there,

From what parts of the Diag Buffer you've sent, it looks like had lost communication with Profibus DP Station 21 on Master Network 1.

Is this device routinely disconnected from your network? Was it powered off for any reason?

What type of Profibus device is using this address?

If you can attach more previous events, it would help.

This fault means :

Distributed I/Os :station failure, leaving state