Re: DRO issue "HEDs in hand"

Hello,

The scales I have here are 600mm length that I bought for $49 so
something changed price-wise.

The way I understand it, the 25CPMM module actually has 2 light
sources in it that are perfectly offset so as to double the
resolution of the scale it is reading. The 2 light sources then send
the signal out and that's what you can then quadrature.

I am using the parallel port based DRO HW/SW from Art Eckstein. I
have it running on a notebook. I have just got a spare desktop
machine and monitor for in by the lathe so I will probably get one of
Dan's cards soon. I do get 0.01mm resolution and have confirmed the
measurments with both actual items turned and the dials on the
lathe.

TTYL, Jeff

--- In CAD_CAM_EDM_DRO@y..., "John A. McFadden" <mcfadden@c...> wrote:
> Jeff:
> Its $85 for 600mm, $50 for 166-200mm lengths (asked about that
length range
> for my Y and Z axis).
> Its a good thing you mentioned EncoderTech, I never did the math on
the
> metric scales, and only looked at the 720CPI scales but took them
off my
> list of possibles when they said that they did not have any longer
than
> 3.25". With .0004" resolution and Don Mauch's method for
protecting the
> strips, it looks like I am good to go.
>
> I am also a little confused by the math, the US Digital encoders
and strips
> can only quadrature out, giving the resolution as four times the
lines per
> inch of the scales, but Encoder Tech's encoders double the
resolution and
> then quadrature it? Seems a little strange to me, but if it works,
it
> works. What are you using to read the output of the encoder? Are
you
> getting .01mm resolution?
>
> John