Where Do The Steps Go ????

[Gads]

Hello all

Started a new build this winter, 6x10 gantry and working out some things
with my gearing I got thinking about something that didnt come up with
my last build.

Question is if you have a stepper motor that has 200 steps per rev. and a
gear train that works out to an uneven value, example 1" rack gear = pi
3.14159... divided by my ratios steps (5.2*200) comes out to .00302 in
full step, .00151 half step etc.. now if my G code is telling things to go to
even numbered positions such as .001, .004 etc.. how are all the leftovers
handled and do you end up with cumulative errors or what may appear to be
lost steps ???

I currently use EMC2 on my mill and all gearing is equal so i never had thought
about this. I know in EMC2 and MACH your step config and calibration will ask
you travel per rev. etc.. This may be a better post for the controller/software
forum but thought rack drive machines would have run into this.

Thanks GADS

[ger21]

Originally Posted by Gads now if my G code is telling things to go to even numbered positions such as .001, .004 etc.. how are all the leftovers handled and do you end up with cumulative errors or what may appear to be lost steps ???

The software keeps track of the absolute position it's always supposed to be at. It never rounds or clips this position number. Whenever you go to a certain position, it will get as close as it can using your given steps per unit. So you're actual commanded position should always be within ~1 step. Whatever that step size may be.