Applies To:
  • CitectSCADA  5.xx, 6.00, 6.00 Service Pack A, 6.10, 6.10 Service Pack A


I configured my communications correctly. I do not have any Hardware alarm on startup (channel is online and unit is online), but I still have #COM displayed on my page.



When using redundant IOdevices, if the standby device is listed before the primary device in the units.dbf, then read errors will occur.

It does not matter whether you run the project as standalone or redundant servers. If you define two redundant devices, and place the redundant device before the primary device in units.dbf, then #COM errors will occur.

To fix this, simply sort the units.dbf in the "right" order (primary device comes first).

Following achitecture changes in v7, this issue will only occur for version 6.1 SPK B and below.