Re: DRO: USDigital new resolutions 250cpi x 4

That's exactly what is done with quadrature encoders. Within the one
housing are two sensors placed so that their bit streams are 90
degrees apart. When one sensor is in the middle of a bar the other
is at the junction between bars. The two bit streams are called the
A and B channels. Search the web for "quadrature encoding" for a
better explanation or try this URL:

http://mobots.com/EeC194/Notes/1999_10_21.html

Once you understand these basics you will see why the resolution is
quadrupled. If you were to use a second encoder it would have to be
positioned very carefully so that its output was 45 degrees offset
from the first encoder. Then you would have to deal with four
channels instead of 2. And, then you would have to come up with
custom hardware and/or software to deal with the four bit steams.
However, this would yield a resolution eight times greater then the
encoding wheel or strip's actual resolution.

--- In CAD_CAM_EDM_DRO@y..., beer@s... wrote:
>
> Now, I've never actually done this, and given the cost of the
encoder, I
> don't ever plan to, but THEORETICALLY, couldn't a guy use two
encoders
> spaced an appropriate distance apart to double the resolution ?
>
> Alan
>
> --
>
> Alan Rothenbush | The Spartans do not ask the number
of the
> Academic Computing Services | enemy, only where they are.
> Simon Fraser University |
> Burnaby, B.C., Canada | Agix of
Sparta