Designing and Managing Behavior Models - Alarm Actions - Clear Trigger -
Beep      Command

Clear Trigger

When you define a Fire Trigger alarm action, you can use a delay to determine when the trigger actually fires. (For details about the Fire Trigger action, see the section Fire Trigger.) After a Fire Trigger action has been initiated, but before the delay has elapsed, you can cancel the firing of the trigger using the Clear Trigger action. A Clear Trigger action cancels any pending triggers of a specified name that have been queued by its own alarm instance.

When you include a Clear Trigger action with other alarm actions, the Clear Trigger action is always performed first. This prevents the possibility of a trigger being fired and then cleared during the same transition.

A good example of the use of Fire Trigger and Clear Trigger is the predefined alarm IfLinkUpDown.

IfLinkUpDown Alarm

This alarm is designed to transition from Ground to Down Trap upon the receipt of a linkDown trigger. When this transition occurs, a Fire Trigger action fires the trigger linkTimer on a three-minute delay. If a linkUp trap arrives within three minutes, the linkUp transition occurs, and a Clear Trigger action clears the linkTimer trigger. Otherwise, the linkTimer trigger is fired, and the alarm transitions to the LinkDown state.

 
  To add a Clear Trigger action to a transition:

1. From the Transition Definition window, select the New Action button.

   A pop-up menu listing all alarm actions is displayed.

2. Select the Clear Trigger action.

   The Clear Trigger Action dialog is displayed.

   

3. Type the name of the trigger you want to clear in the Trigger Name field, or select it from the Trigger Name drop-down list.

   Pending triggers of this name will be cleared only in the alarm instance that invokes the Clear Trigger action.

4. Select the OK button in the Clear Trigger Action dialog.
5. Select the OK button in the Transition Definition window.
6. Select the Save button in the Alarm definition window.