8526: COMM BOARD: No cyclic connection

Hi,

Relatively new to Seimens but not to industrial controls.  I am working with an S7/300 communicating with a S120 controller,  This system has been running fine for about 6 years but recently has thrown communication fault.   The fault is 8526: COMM BOARD: No cyclic connection.   I have been able to establish TCP/IP communication with the both servo controller and drive via Starter. (This is where the the alarm is showing up).  The PLC SF light is on, I presume due to the alarm on the servo controller.  I can also connect and go on-line with the PLC.   In the comm blocks to the servo controller there is nothing being read from the controller.  I have looked at the hardware settings and all looks in order.   So in a nutshell.  I am able to communicate with the servo controller TCP/IP via Starter as well as see the hardware configuration.  I also am able to communicate PLC to an HMI app via PBDP so the PLC PBDP comms appears to be working. So a few questions: Is the PBDP between the servo and PLC running in parallel to the TCP/IP for configuration on a PC?  Can the PBDP portion of the comm card on the servo controller fail but still maintain TCP/IP communication? How can I verify that the comm card on the servo controller is fully operational via the starter program diagnostics? 

Hi,

is the Communication between the S7 and the S120 with PROFIBUS or with PROFINET(CBE20)?

Regards
Christoph

Talking with a few others I guess it is Profinet as it is running in an Ethernet backbone. 

Hello,

ok then check ti Name Of Station of the devices and check the topology.
If you open the Tópology Editor in HWConfig there is a Online mode where you can compare the offline an the Online data.

Regards
Christoph