Re: Interfacing EMC with Bandit drives

Jon-
Boy, Do I have mud on my face. I now realize I made a mistake in
when I typed in my table. My machine does just as you say.

After going through the logic on your suggested schematics, I got a
better understanding of the terms "full step" and "half step". The
full step circuit omits every other state. I don't know if a motor
would accept an input which skips steps. If it does it looks as
though one has given up resolution. Why would one want to do that?

Jack Ensor

--- In CAD_CAM_EDM_DRO@y..., Jon Elson <jmelson@a...> wrote:
>
>
> Jack Ensor wrote:
>
> > I compared your step table with mine and see that yours seems to
be
> > what it should be. However my Bandit does just as I listed in my
> > table. It skips the first state in your table. I don't know why.
>
> Hmmm? Besides the movements being 'lopsided', ie. moving 6 half
steps
> and then jumping one whole step, it makes the motor move with
> steps of 400 * 8/7 = 457.1429.... steps/rev! That's a particularly
wierd
> number. If this is so, then either it has a VERY odd leadscrew,
> or some sort of pulley ratio that compensates for this, like
> 28 : 32 tooth pulleys.
>
> >
> > Maybe it is broke and I don't know it. It seems to have the
accuracy
> > it should.
> >
> > Thanks for the suggested circuits for converting step/direction to
> > make step phase signals. Could you explain the difference between
> > half step and full step. Why would one choose one over the other?
>
> Your machine is doing half-steps. These may be a little smoother,
> as well as giving twice the position resolution. That is the major
> reason for half stepping.
>
> Jon