CEX-BUS CI854 "Taken out of ring by another Master, check System conf."
The objectname "2" means the CI854 Modul on the CEX Bus.
What could be "another master"? It sounds like a address conflict, but there is no change of hardware or something like this.
I changed every CEX-component. After the controller reboot there's about 20min no warning, after that the object warns a few times every minute.
See the HW-configuration in the attachment. Any ideas which source may be responsible for the alarm?
From the information you posted I cant guess which other device may be trying to take control of the bus.
Although the Profibus standard does allow multiple masters on the same bus ( but only one fixed master for each slave unit ), the CI854 unit will not work in this configuration. This is the reason why, for example, Siemens CP342 interfaces must be configured to work as a "passive slave".
A profibus analyzer like this one - http://www.procentec.com/profitrace2/... - will allow you to analyze all of the traffic on the profibus and see exactly what is happening when the fault occurs. ( it is also pretty good at diagnosing cabling faults )
I was faced this problem once so on checking the profibus connecttion using profibus tracer tool i found faulty profibus connector so on replacing the faulty one it works fine.
Generally you can't judge the exact faulty connector in the profibus line so better to use tool to find it.