Applies To:
  • CitectSCADA 7.0
  • CitectHMI 7.0
  • CitectFacilities 7.0


Alarm page which shows alarms from all the clusters freezes when one of the clusters is disconnected in a multicluster environment. This only happens when the cluster gets disconnected abrubtly and not when its shutdown properly. The issue can be easily reproduced by starting up citect and disconnecting the ethernet cable in the cluster 2 machine.



The issue is caused because some the TCPIP packets are not delivered and the timeout for these TCPIP packets is not reached. The alarm page waits for the TCPIP packets to get delivered or wait for the timeout period. Unfortunately the timeout period for these packets are not controlled by citect and is controlled at the windows level.

The only way to fix the issue is by modifying the TCPIP windows registry settings like DefaultTTL, KeepAliveTime etc.