Thanks for the quick reply Glenn and Kirk,
The scales are quadrature output - Mitutoyo brand.
I recall the list discussion on the difficulty of using the linear scales
sometime last year or perhaps earlier. These are available close to me for
a decent price so I thought this might be a way to go. Unfortunately the
party tossed the DRO box so its just the scales, cabling and brackets. I
hope to look closer at them tomorrow and maybe take a chance on them.
Thanks again and I am open to any other thoughts.
On Sat, Feb 27, 2010 at 11:14 PM, Kirk Wallace
> On Sat, 2010-02-27 at 22:21 -0500, BRIAN GLACKIN wrote:
> > I may pick up a set of linear scales which were part of a DRO for a
> > machine.
> > The DRO box was fried but the scales are reportedly still working. If I
> > these scales, will I be able to hook them up using one of the available
> > boards (mesa or pico)? I have a 13.5X40 lathe I am considering using
> > for.
> > Any suggestions including what to look for with used scales are
> > Brian
> If the scales have quadrature output, then you should be able use a
> parallel port, Mesa or Pico.
> Some scales don't use quadrature, so at best, you would need a
> Using a linear scale for the primary encoder is not recommended. Usually
> there is a lot of feedback latency between the axis motor and the
> encoder, which causes feedback loop instability. Some here have used
> linear scales in combination with motor shaft encoders, but this is not
> for novice integrators.
> Compared to a proper motor or ball screw rotary encoder, the most common
> linear scales don't have very high resolution and rotary encoders can be
> cheaper. Although this comment may be out of date, because a lot of the
> newer scales have had pretty high resolutions, but still not like a
> You may want to consider fixing the DRO display or selling the scales
> separately and use the money to get rotary encoders (,or beer).
> Kirk Wallace
> California, USA
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