Re: [CAD_CAM_EDM_DRO] Mitutoyo Linear Scale AT715 signal format?

THe scales are probably distance coded not straight quadrature.

Harko

On 9/2/06, Jon Elson <elson@...> wrote:
>
> mayfieldtm wrote:
>
> >Does anyone happen to know the signal format for Mitutoyo Linear
> >Scales, series AT715?
> >I want to interface one to a microcontroller such as a PIC and need
> >the pinout and signal information.
> >These scales are intended to be exclusively connected to Mitutoyos KA
> >Counters.
> >These scales are Absolute reading units and I'm assuming they spit out
> >a continuous stream of serial data to indicate current position.
> >Or they send data upon a request, or???
> >
> >
> Probably they are just quadrature incremental encoders with a special
> index
> track. The way most of these work is that the number of quadrature
> counts between
> index marks is different between every pair of index marks. So, you
> only need to
> pass by any two adjacent index marks, and you know where you are. This
> is the
> simplest form of absolute encoder, and it takes no more electronics than
> a standard
> encoder with one index mark -- just 3 optical channels. A little bit of
> software
> in the readout box computes the absolute position. This requires a
> small move
> of the machine after turn-on before the absolute calibration is set.
>
> Jon
>
>


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