What you need to know is where the encoder is fitted, (final counts/rev) and what the system you are using will allow, and what resolution do you want/need.
For e.g say you have an encoder on a motor which operates a .25" pitch ball screw directly.
If you had a 1kpulse/turn encoder and most controls will allow increasing this resolution on a quadrature encoder to x4.
Therefore this will result in (4x1000)x4=16,000 pulses/inch which equates to a resolution of .0000625 per pulse.
If you have any gearing between motor and ball screw this will affect the resolution proportionately.
Al.
CNC, Mechatronics Integration and Custom Machine Design
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.