that may be true pwm but the 0 is also the base line / anchor point, if that shifts, everything does and you'll have to recal the entire thing then. this is what i was looking for, see if there was a shift. you can tweak the 20 (or 15 if it's an air actuator) and only do that one ok, but if you change the 0 any, now you have to redo the 20 as well, and if for some reason doing a step or flow mapping, every point then as well.,
Aaron