Applies To:
  • CitectSCADA 5.xx

1. You cannot talk to multiple PLC's if they have all have the same TCP/UDP 'port number' configured.

2. You cannot run multiple applications (or different processes) addressing the same TCP/UDP destination 'port number' (in the PLC).

That means you can not run Citect and SysWin V3.2 at the same time to the same PLC. Typical problems are "Destination Node Busy" in SysWin and in Citect you get communication errors like;

Wed Nov 25 13:35:19 1998 44:37:56:737 Error: General error
READ 0008 Port2 PLC2 D2612 1
Generic 000008 Driver 00098820 (0x00018204)


1. When using the OMFINS driver, configure a different port number for each PLC.

2. There is only one receive buffer in the PCU01. There is no work around in Citect or SysWin for this. The Omron CV500 has 16 buffers, which overcomes the problem.

Also beware if you have two Citect I/O servers accessing the same PLC. This should not be a major problem with I/O server redundancy though.