Re: [CAD_CAM_EDM_DRO] Encoder question

Roy J. Tellason wrote:

>On Monday 04 April 2005 12:50 pm, Jon Elson wrote:
>
>
>>babinda01 wrote:
>>
>>
>>>Hi,
>>>I am hoping someone can help with a problem I am having.
>>>I have a linear encoder which only has 2 chanels A, notA & B, notB. I
>>>need to have a Z, notZ pulse so that I can set up homing. Is there a
>>>circuit that can be made to 'generate' a Z phase????
>>>
>>>
>>No, you can't make the index (Z) signal from A and B. the A and B
>>quadrature signals just repeat every cycle of the pattern. You
>>need a separate optical track to generate the Z.
>>
>>Jon
>>
>>
>
>What is this "Z", an index pulse? One per rotation kind of thing?
>
>

Yes, exactly. It is a pulse that goes true over a very short angle of
movement,
and is often referenced to a particular transition of the quadrature
signal, as well.
It is usually once per rev on shaft encoders. Some linear scales have the Z
repeat every so often, or arrange it so that its relation to the
quadrature signal
allows the DRO to figure out which specific repeat of the Z it just
passed over.
That's how the absolute DRO's work.

Jon