Indefinite alarm suppression

When you configure the following fields on the Main tab of the almsuppression Row Edit dialog box as indicated, the system considers alarm suppression to be "indefinite", and will not create an alarm suppression timer:

• Parent Alarm/Control: 0

• Parent Return to Normal: A non-zero value

So long as the parent remains in the alarm state, the system continues to suppress the child. A point comes out of a suppressed condition when either the parent returns to normal, or the child enters a state that is either not suppressed or not subject to alarm suppression.

The system ceases to generate telemetered alarms for points in a suppressed state. This method of handling alarm suppression can have a potentially undesirable consequence: if the child point is in an unsuppressed alarm state (for example, HiHi), and then enters a suppressed alarm state (for example, Lo), the HiHi alarm remains on the child even though the point is no longer in the HiHi state. This situation arises because the system ceases to generate further alarms to remove the pre-existing HiHi alarm from the Alarm Summary window while the point is suppressed.

Optional functionality controlled by a configuration setting enables the system to generate stateless alarms for child points in indefinite alarm suppression ( refer to Configure the generation of stateless alarms).