Dear all,

We have a project that was working fine until last March. We have the following configuration:

Last March we started losing instantaneously the Profibus communication every 20-30 days. By instantaneously I mean for 1-2 seconds. A loss that was causing our machines to stop, reset and start again. The frequency of loss was increasing by the time, driving us to now days that the communication is lost for 100-150 times per day for 1-2 seconds. Few days we replaced all Repeaters and even the CP443-5 with a new one. We checked the cables of the network, even replaced some parts, and also replaced a big number of Profibus Connectors with new ones. Profibus cables are laid min 1m distance from power cables, so I don’t believe we have any interference from them. Total length of the network is 760m and baudrate is 187.5kbps.

Each segment of the repeater is max 70m and the max number of devices on each segment is max 18.

Few days ago we had a failure on profibus network which caused a failure on CPU, causing a total failure of the system for almost 8 hours until we got to the plant and warm restart the CPU.

The total failure happened again yesterday for 7hours and we warm restart the CPU again.

I attached the CPU logfile after the second failure if that helps.

hi Antri, 

There are much Threads about this kind of failure in this forum here. Just search for the Event-ID 494D and you will see. 

This failure is difficult to determine. 

I advise you to start a Support Request. The Support-guys maybe can help you with the information in the Z1, Z2, Z3-data.

regards,