Applies To:
  • CitectSCADA

Pauses in the running of Citect when using Disk PLCs may occur under the following conditions:

1- When the RUN directory is on a different PC, network timeouts may occur due to some file requests from the Diskdrv disk PLC driver.  This is because the Diskdrv disk PLC driver checks for the existence of the storage file, first along the path formed by appending the run path to the entered path, before checking the entered path alone.  If the the path formed by the concatenation of the entered path and the RUN path does not exist, perceptible pauses may occur in the running of Citect due to network timeouts.

2- When the primary disk file is located on a different PC such as a file server, and the path to that file has become invalid.  The path is checked regularly by the driver when writes are occurring, and this means again that network timeouts may occur causing perceptible pauses in the running of Citect.


CIT has confirmed this to be a problem.  These problems have been fixed in version 3.02 of the DISKDRV disk PLC driver, through an improvement in the algorithm for checking paths, and the use of a separate thread for the writing of files.