The ability to Unacknowledge Alarms is disabled on most systems by default. (Its permission is typically denied on a per server basis.)
Depending on the system configuration, it may be possible to unacknowledge alarm(s) that have been acknowledged, but for which the abnormal condition still exists (that is, alarms that are in the Acknowledged Uncleared state). You unacknowledge alarms using the Unacknowledge or Unacknowledge Alarms options. (A further option, Unacknowledge with Comment can also be used—see Unacknowledge an Alarm with Comment.)
When you unacknowledge an alarm:
- The item’s Alarm Status changes from Acknowledged Uncleared to Unacknowledged Uncleared.
- An entry is logged in the Event Journal, stating when the alarm was unacknowledged and by whom (the User that was logged on to the workstation at the time)
- The position and color of the alarm in Alarms Lists and the Alarm Banner changes—the alarm appears alongside other Unacknowledged Uncleared alarms, and uses the color assigned to that Alarm Status.
- The number of unacknowledged alarms increments by one on the Alarm Bell Button.
NOTE: In addition to the pick actions mentioned here, ClearSCADA provides various methods that enable activities to be performed on alarms programmatically. This includes methods that are designed to trigger activities at specific times, such as the AcceptAtTime method that can be used to specify the time at which ClearSCADA is to acknowledge an alarm and to optionally log a comment for that acknowledgement. For more information on such methods, see the Database Schema (specifically the Methods section in the CAlarm class).