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

With a GEMLAND network of PLC's, Citect appears sluggish when one unit is not communicating properly.

If a PLC stops communicating, Citect will continue to request data from the PLC until it has determined that the PLC should be declared off-line. Prior to declaring the unit off-line, Citect gets clogged up with requests on that PLC. The result is that Citect updates displays very slowly. Once the bad unit is declared off-line the Citect will return to speed.

This is a limitation on the design of the GEMLAND protocol which is out of Citect's control. 

The problem can be minimised by reducing the time it takes for a PLC to be declared Off-line. In the CITECT.INI file under the [Gemland] section use the standard Timeout setting

Timeout = 5000

Tune this setting so that the units come on-line as they are supposed to but the interruption to communications is minimised.