Timed parent alarm suppression

With timed parent alarm suppression, child alarms are suppressed on the basis of the parent’s alarm state. Unlike parent control alarm suppression, timed parent alarm suppression is not concerned with suppressing alarms that are directly related to a Controller's command to a field device.

When a parent with alarm suppression records goes into alarm, the children’s alarms are suppressed for a configured amount of time (for example, a timeout value). Child alarm suppression is canceled after the timeout value has expired. When the timeout value expires, the system reevaluates the alarm state of the children.

Note: Timeout values are not reset if the parent toggles between alarm states.

In the case of alarm suppression based on the child alarm state, child alarm suppression is canceled when a non-suppressed state is reached. In this event, the parent alarm timers for alarm, return-to-normal, and alarm hold-off are either canceled or prevented from being triggered. For example, assume that a child is configured for a timed parent alarm suppression in the Normal, Hi (High), and Low alarm states. If the record’s parent changes alarm state and triggers alarm suppression, the child’s alarm remains suppressed while the child remains in the Normal, High, or Low alarm state. If the child reaches the High-High or Low-Low alarm state, its alarm suppression is canceled immediately and the system generates an alarm.

Timed parent alarm suppression only suppresses child state alarms that result from data krunching. Other types of alarms (for example, command failure) execute as normal. Timed parent alarm suppression is supported for analog, rate, multistate, and status records.