Re: How to establish repeatable home position w/steppers?

Dave,

.0002" is getting into the ballpark. .000125" is my theoretical
resolution so that's what I'm shooting for.

Maybe some sort of encoder device on the motor shaft would be the way
to go?

thanks,

Doug




--- In CAD_CAM_EDM_DRO@egroups.com, dave engvall <dengvall@n...>
wrote:

>
>
> There has been some discussion of limit switchs/home on the list in

the last month or so. One person was getting a thou or so out

> of micro-switches ( he did not state his limit of resolution) and I

get 0.0002"repeatibiliity from hall effect devices. They might

> be better than that but that is my resolution limit. :-)
>
>
> Dave
>
> dougrasmussen@c... wrote:
>
>
> > Group,
> >
> > On an open loop stepper system how do you establish a repeatable

home

> > position? I'm thinking of a home position that will repeat to

within

> > the resolution of the machine.
> >
> > I can't see that normal, every day limit switches will do the job.
> > Dial indicators would be a pain, but would work provided they

didn't

> > get bumped or readjusted. Some very old machines used a vernier

dial

> > which was manually stepped to position.
> >
> > So, what method are most of you using?
> >
> > thanks,
> >
> > Doug
> >
> >
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