I am in the final stages of implementing my program. Currently I have to overcome two obstacles . #1 corresponds to the attached VI "My stopwatch" The round LED starts counting the time and stops it. Problem is even if I turn it off it, the timer keeps counting the seconds when I turn it on again. I want it to accumulate only the time it spent in the on position. How do I do this? #2 corresponds to the VI "array of time". I want to use "My stopwatch" as a reentrant subVI in this VI. I want the round LED Boolean array as the control to switch the stopwatch on and off. Thanks for all your help. mhaque

To use it as a subVI, it is easiest to use globally initialized feedback nodes. Here's a quick example. (Place both VIs in the same folder, then run CallTimerSubVI) You are using way too much code. Please rethink what you did! Also study my example. Instead of 24 shift registers use three, containing arrays of 8 elements (or the number of timers you need). You need a resolution of one second, so place a wait inside the loop. There is no need to spin it 10 million times per second, you are just wasting cpu cycles and starving all other programs. One diagram constant of 1000 is sufficient (instead of 16!). You can branch the wire. Why divide both values by 1000, then add? Add first and divide once! Why invert the booleans, just swap the cases if needed? (Even if you really want to invert all booleans, do it once on the array side.) This is a small VI, why maximize to the screen? Note that my code scales well. A few minor changes would allow it to be used with 100 timers. To do the same with your program design would be impossible. 😄