Re: [CAD_CAM_EDM_DRO] Re: EMC and stepper driver

Wally K wrote:

> Tim:
>
> Let me ask you this question then. When talking about EMC and
> driving steppers. Do people know for sure that the problem is
> unevenly spaced steps at the higher speeds, or are steps actually
> missing.

absolutely, with TOTAL certainty, we are sure that it is ragged step
timing.
If you slow everything down, steps are never lost. If you use a step
driver
that is more tolerant of step timing jitter, no steps are lost.

> And one more bonus question on EMC. I have seen talk about encoder
> feedback for steppers. Were i assume the encoders mount on the
> stepper. Is there a setup in EMC that allows use of the DRO freeware
> boards and using linear scales for absolute position. Assuming
> linear scales can be hooked up to these boards.

Yes, the Dan Mauch DRO board is supposed to be supported.
The only possible problem with linear scales and steppers is that
hunting could get quite unpleasant, as the encoder is on the other
side of the leadscrew and other machine backlash sources.
It could sit there all day rocking back and forth .001" or so.

Jon