How to prevent this trigger loop

[Nathan0093]

Initial Units
    Events
        Map initialization
    Conditions
    Actions
        Unit Group - Pick every unit in (Units in (Playable map area)) and do (Actions)
            Loop - Actions
                Trigger - Add to Extra Damage <gen> the event (Unit - (Picked unit) Takes damage)

Extra Damage
    Events
    Conditions
        (Unit-type of (Triggering unit)) Equal to (==) Footman
        (Unit-type of (Damage source)) Equal to (==) Knight
    Actions
        Wait 0.01 game-time seconds
        Unit - Cause (Damage source) to damage (Triggering unit), dealing 20.00 damage of attack type Normal and damage type Force
        Set loc = (Position of (Triggering unit))
        Floating Text - Create floating text that reads ((String((Integer((Damage taken))))) + !) at loc with Z offset 0.00, using font size 10.00, color (100.00%, 100.00%, 100.00%), and 0.00% transparency
        Floating Text - Change (Last created floating text): Disable permanence
        Floating Text - Set the velocity of (Last created floating text) to 15.00 towards 90.00 degrees
        Floating Text - Change the lifespan of (Last created floating text) to 3.00 seconds
        Floating Text - Change the fading age of (Last created floating text) to 1.00 seconds

I was playing around with these triggers, but I encountered a problem. What I want to happen is when x unit attacks y unit, x would deal a certain amount of extra damage to y. The problem is that after x deals the extra damage, that damage repeatedly triggers this event until y unit dies. Is there anyway to prevent this loop from happening? I tried to look for a condition that detects the type of damage dealt, but I had no luck. A variable for damage type (unknown, normal, force, enhanced, etc.) is there, but there is no condition to check for the damage type. Help?

 

[DrEvil]

This should stop the infinite looping :

Trigger - Turn off (This trigger)
Unit - Cause (Damage source) to damage (Triggering unit), dealing 20.00 damage of attack type Normal and damage type Force
Wait 0.30 seconds // < -- 0.3 is about the minimum it waits anyway
Trigger - Turn on (This trigger)

 

[Nathan0093]

Problem solved. +Rep