Re: [CAD_CAM_EDM_DRO] Digest Number 2587

Bob is right. If you have designed for proper stepper operation you
should not have lost steps. However, as things age or your lube system
fails, it is possible that the extra protection offered by encoder
feedback directly to the EMC might be desirable. It can be accomplished
with the Kulaga/Mauch dro board and an emc motion driver named
smdromod.o. A couple of us have found this driver to be broken for more
than two axes. We should have that sorted out before long.

Ray

>    From: "Robert Campbell" <bob@...>
> Subject: Re: steppers+feedback+emc
>
> If your stepper system is designed properly and you are not trying to
> cut too deep in one pass, you should not be loosing steps.
>
> Using my Porter Cable 3.25 hp router, I generally make three passes on
> a 3/4" piece of red oak.  With a 1/2" MDF, I make it in two passes.
>
> My cnc router uses 350 oz/in  steppers driven by Gecko drives. My lead
> screws are 4 turns per inch.
>
> Bob Campbell
>
> ----- Original Message -----
> From: "awallin25" <anders.wallin@...>
> To: <CAD_CAM_EDM_DRO@yahoogroups.com>
> Sent: Tuesday, September 24, 2002 9:40 AM
> Subject: [CAD_CAM_EDM_DRO] steppers+feedback+emc
>
> > after milling some mdf with a stepper controlled table I think i need
> > to add feedback(encoders) to eliminate missed steps...
> >
> > my question is:
> >
> > would it be possible to hook up the encoders directly to the pc and
> > let EMC read them and act accordingly, ie. implement a PID controller
> > in (real-time) software ?
> > the parallell port pins won't be enough(?), but what other options
> > are available ? (serial?)
> >
> > also, a question for EMC users: how does PC speed affect the speed at
> > wich you can do interpolated(linear, cubic etc.) runs on a mill?
> >
> > thanx for any answers.