Here is how you do the math. I will give you mine as an example. What we need to know is, How many pulses from Mach will it take to move the machine 1 of your units? (inch,mm, degrees) Mine is in inches. 1 inch = 10,000 pulses on mine. This is how I came up with the number.

My steppers have 200 pulses per revolution. ( 360 degrees divided by 1.8 degrees = 200 )

Micro stepping = 10. So 200 X 10=2,000

Motor to screw gearing is 1-1. So 2,000 X 1=2,000

Screw lead is .200 of an inch. My screw will have to turn 5 rounds to move the nut 1". 1.0 divided by 0.200=5. So 2,000 X 5=10,000.

Another note. When designing a system try to make the math come out so that your steps per can be divided evenly into the highest resoloution you will be trying to hold or higher. For arguments sake lets say you had a system that had 100 steps per unit and you wanted to travel .001 units. The closest you could possibly get is .009 units from where you want to be. Now say you have a set up that uses 950 steps per and want to move .001 units. You can get much closer but still no way of getting there exactly. You will be slightly under of over your target.

Brett