Applies To:
  • CitectSCADA 3.xx, 4.xx, 5.xx

Citect will sometimes show the "Driver Not Responding" error in the kernel. When examining the settings for the protocol driver having the problem, you will see (Retry + 1) * TimeOut (seconds) > Watchtime. 

CIT has confirmed this to be a problem in Citect for Windows versions 3.xx, 4.xx and 5.xx. With the settings (Retry + 1) * TimeOut (seconds) > Watchtime, then under a timeout condition, the IO Server may time out the request before the driver can time out the request. This situation results in the "Driver Not Responding" error occuring in the kernel. Users using the default values for a driver should normally not be affected by this problem, as the default values for a driver should satisfy the above equation. The change prevents the IO Server from timing out a request for a default period of 5 minutes. This should always allow a driver to timeout a request before the IO Server. The new IO Server timeout parameter introduced by this change is [IOSERVER] CancelTimeout, and is measured in seconds. The default is 300 seconds (5 minutes). This parameter should not normally need to be modified.

This problem has been fixed in version 5.21 Service Pack B.