Applies To:
  • CitectSCADA
  • CitectHMI

When used in conjunction with Citect’s OPC driver, some OPC Servers exhibit the behaviour of shutting down immediately after they have been started by CitectSCADA. It is possible for this to be an intermittent problem, but generally it is reproducible and repeated every [OPC]WatchTime seconds as CitectSCADA tries to reconnect.

OPC Servers that go through a series of startup states before reaching OPC_STATUS_RUNNING tend to demonstrate this behaviour.


Citect has confirmed this to be a problem in OPC version and earlier. This problem has been fixed in version via the citect.ini parameter [OPC]ServerOnlineStates.

[OPC]ServerOnlineStates defines the list of OPC Server states that the driver considers online. The format is a "|" separated string (spaces are not allowed) of the following possible states:

- "TEST"

By default "RUNNING" is the only state regarded as online. If you are experiencing the shutdown issue it is recommended that the following states are used:



opc server shut down startup state status noconfig status_suspended