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

Citect runtime starts but cannot establish communications with a PLC. The only error is a hardware alarm, PLC is offline, cannot talk.

I have installed a card to talk to the PLC. After, the PC had been rebooted but still no communications. Citect was even reinstalled but still no communications could be established.


Checking NT diagnostics reveals that the card is installed but the WinRT "device" is not appearing;

Administrative tools | Windows NT Diagnostics | resources | devices.

Also checking the Winnt\system32\drivers folder reveals that the "WinRT.sys" file was installed but further investigation shows that there are no settings for "WinRT" in the system registry. This indicates an O/S problem.

The solution is, after installation of a card and/or software, the relevant NT service pack needs to be reloaded. After this, Citect may need to be reinstalled to correctly install the WinRT device. The system should communicate correctly after a reboot.