Alarm disablement, inhibition, and suppression

You can turn alarms "off" or ignore them without actually removing the alarm configuration. You can either disable an alarm, inhibit it, or suppress it.

Alarm disablement and inhibition is controlled at the alarm provider. Suppression is controlled at the alarm consumer. For more information on providers and consumers, see Alarm providers and consumers.

• Disablement. You disable an alarm at the alarm provider by setting a flag that marks it as disabled. No matter what alarm conditions occur, the item is never put into an alarmed state. For information on dotfields you can use to disable an alarm, see Enabling and Disabling Alarms for a Tag or Alarm Group.

  You can disable or enable all of a tag’s alarms at one time. Also, for an alarm that has sub-states, you can disable each sub-state individually.

• Inhibition. You inhibit an alarm by:

  1. Adding an "inhibitor" tag to the alarm configuration in WindowMaker. The inhibitor tag is used at run time to mark the alarm as inhibited.

  2. Setting the inhibitor tag to True or False at run time. When the inhibitor tag is False, the alarm is handled normally. When the inhibitor tag is True, the item cannot alarm.

  Each alarm sub-state can be inhibited by a different tag, and you can leave some sub-states with no inhibitor tag assigned.

  Assigning a tag as an inhibitor tag for an alarm increases its cross-reference use count.

• Suppression. Suppression causes an alarm consumer to ignore certain alarms. If an alarm matches the exclusion criteria, it is not visible. That is, it is not shown on a display, printed, or logged at that particular alarm consumer.

  The actual alarm generation is completely unaffected by suppression. Alarm records can still be logged into alarm history.

If an alarm becomes disabled or actively inhibited while the item is in an alarmed state, the item is forced to a different (valid) state. What that state should be depends upon which states are available and whether they have also been disabled. This activity is handled by the alarm provider according to the type of alarm, limit values, and so on.

An alarm that is disabled or actively inhibited is not waiting for an acknowledgment. If the alarm has sub-states, it can only be waiting for an acknowledgment on sub-states that are still available.