For the analog I/O module for the Allen Bradly 1200, I want to use voltage reading over amperage readings which seems to be what most people use.Is there a reason that current is used over voltage for analog I/O? difficulty? We are using 2 IR sensors to center an object for a robot manipulator. The IR sensors use voltage to determine distance. In a utopian world I want both sensors to read the exact same voltage in order to determine that the object is centered. I realize though, this is difficult to fine tune movement in order to get them equal. My question is are there tolerances that can be used in the compare functions? Like that IR one is equal to IR two within a small +/- tolerance. Is this possible?