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

The alarm scan time parameter will tell Citect at what rate to process the alarms. This parameter defaults to 500ms. At this rate Citect will try to process the alarms every 500ms. However if Citect cannot read all the alarm data from the I/O Device within 500ms, the alarms will be processed at a slower rate. For example, if it takes 800ms to read all the alarm data from the I/O Device, Citect will then process the alarms every 800ms.

This option is useful if you want to tune the performance of Citect. For example slowing down the alarm scan time will cause the Alarm Server to use less CPU (as it does not have to process the alarm records as often). It will also reduce the amount of data read from the I/O Device so that other processed (Trends, Reports, and the current page) will get their I/O Device data more quickly.