from logic, to a physical action, how bizarre

[iceman2013]

Hi guys. I'm wondering if someone could explain how a physical action is processed from a controller's software program. I understand how an input will go through it's logic to perform a certain output, this is in many books. But how is that output made? When logic in a controller calculates a change necessary for an output, what happens between the logic output, and the physical output signal? Seems so mysterious to me.

[iceman2013]

Neva-mind...it's done through a d/a, a/d converters. Still seems mysterious though.