Decrement PtByPt (Not in Base Package)

Begins at start and decrements counter by one each time the VI is called when activate is set to TRUE.

start is the initial value of counter whenever you set activate to TRUE.
activate, when TRUE, initiates a countdown beginning at the start value. When FALSE, the VI does not count down.
initialize, when TRUE, initializes the internal state of the VI.
counter is the decremental value where counter = (previous counter - 1). The value of counter changes only after you set activate to TRUE.
zero crossing is FALSE by default. If counter reaches zero, zero crossing becomes TRUE and causes the value of counter to become start again.