[RyanN]

There's a reason why you have an LabVIEW Encoder block. If I remember correctly, most of the robot code only gets executed every 40ms. If your sensor goes through a transition state during those 40ms, then it won't be counted.

Now I haven't looked under the cover for the encoder VI, but I would have to imagine it is using some sort of an interrupt, or is polling that digital input very quickly.

You may want to take a look at the encoder block under sensors in the WPI library. If you want to make your own, place a very quick (5ms or less) while or timed loop in your Period Tasks VI.

Do what Alan said below. I believe that will work better than what I recommended.