I did exactly as you suggested and added an additonal check to the If statement to only output a value if device.fix[6] is less than a constant number (mine was consistently returning NaN for the first iteration), and it works exactly as expected. It now takes 2 or 3 seconds to return a (good) value, instead of returning a (bad) value in a fraction of a second. Thanks tuxfoo, and everyone else that responded. Forums are awesome.