Applies To:
  • CitectSCADA 1.00, 1.01, 1.10, 1.11, 1.20, 2.00, 2.01

The TISOFT CVUTA.DEV driver is incompatible with Citect TIWAY protocol driver. You must remove this driver from the CONFIG.SYS file before running Citect with this driver. The TISOFT CVUTA.DEV driver is used by TISOFT to communicate to the PLC via the TIWAY card. If this driver is installed, you will get the error "Unit offline, cannot talk" hardware at random times. The PLC will go offline and then online again - generating this hardware error. It may also get into a state where the I/O Device will remain offline and all communication will be lost. 

Remove the CVUTA.DEV driver from the CONFIG.SYS file.