The PMD-51031-R is a low cost RS-232 based 3 Amp/ph Stepper Driver, with 3 Digital Inputs, 2 Digital Outputs, in addition to 2 Limit Switch and one Reference Inputs. Test operation of the stepper may be done locally, on both directions, without the need of an RS-232 source. Limit Switches may be of either Normally Open or Normally Closed nature, and should be defined by the user. 5 Leds provide a local indication on the power, motor and limit switches status. Step Resolution may be selected between 400 to 4000 Steps per Revolution (20 micro step per step), while the current is adjusted by both jumpers and a potentiometer, in order of getting a better resolution at the lower range.