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

I have used the Computer Setup Wizard to configure a Citect Display Client. However, on startup I get the message: "Opening \\.\ Com4 of Board1: Error 'The system cannot find the file specified' " Why is my display client attempting to initialise a COM port on a serial card which resides in my I/O Server? 

If the I/O Server name is set in the Citect.INI file, but the I/O Server is not enabled then Citect will still try to initialise any ports configured in that I/O Server. This is to allow for ComOpen() functionality on non I/O Servers. Refer to On-line help for more information on ComOpen(). You can get around this by changing the Citect.INI parameter [IOServer]Name= to some nonexistant server name. Note that leaving it blank will generally not work.

Note: In V5.21 and higher, it is no longer possible to use the Com functions on a display client. You will need a server licence.