Applies To:
  • CitectSCADA 5.20

With Citect for Windows 5.20, TCP/IP sockets are now used as the mode of communication between remote computers for CtApi. When the computer you are trying to be connect to through ctOpen is not running, then a timeout will occur.

Currently the timeout is based on the memory mode of communication, which retries up to 20 times. However this is not practical for sockets as they have their own timeout mechanism. Since the default mechanism for sockets will take about 20 seconds to timeout, this will mean that currently ctOpen will take about 7 minutes to timeout.


The solution is for ctOpen not to use any timeout mechanism for TCP/IP communications as Windows will do it itself.

CIT has confirmed this to be a problem in Citect for Windows versions 5.20. This problem has been fixed in version 5.21.