Step input to a servo drive is fine if the if the smarts of the hardware performs a quality interface between the step input and the PID control of a servo motor. The beauty of step input servo drives is that you are not locked into purchasing expensive control software and hardware. Our servo drives have step input with a dual mode output where you can control a sevro motor via PID and current limit trim pots as well as the ability to control a servo amplifier via a +/- 1 -10V scalable output and will work with any step and direction software, so far we have not encountered any inconsistancies or inaccuracies. I think Mach2 will be perfect for your application Zeph
"A Helicopter Hovers Above The Ground, Kind Of Like A Brick Doesn't"
Greetings From Down Under
Dave Drain
Akela Australia Pty. Ltd.
(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)