Re: [CAD_CAM_EDM_DRO] Stepper motors as encoders

mouse driver encoder is the best in low cost.


shabbir

At 10:42 AM 8/19/01 +0100, you wrote:

>HI,
>
>Sounds like we're back to modified mouse electronics again here - big pulley
>on the machine shaft and rubber band drive to the mouse encoder shaft?
>
>Ian
>--
>Ian W. Wright
>Sheffield UK
>www.iw63.freeserve.co.uk
>----- Original Message -----
>From: "Jon Elson" <elson@...>
>To: <CAD_CAM_EDM_DRO@yahoogroups.com>
>Sent: 19 August 2001 06:39
>Subject: Re: [CAD_CAM_EDM_DRO] Stepper motors as encoders
>
>
>> grant.fair@... wrote:
>>
>> > I am thinking of playing with stepper motors as shaft encoders. Has
>> > anyone had any luck with this approach?
>> >
>> > In practical terms, 100 pulses per revolution is the best resolution
>> > which would be available. The main virtue of this approach would be
>> > low cost, since .9 degree/steppers (which give only 100 ppr) seems to
>> > be the smallest step size widely available from surplus sources, where
>> > they are available in the $2 range. The electronics to interface a
>> > stepper so it outputs 5V pulses is cheap - 2 comparators, and a few
>> > R's, C's and diodes, plus a 5V power supply.
>> >
>> > Any comments? Would 100 ppr have any value with DRO's? Of course
>> > greater resolution could be achieved mechanically.
>>
>> 100 PPR is not so great for measurement systems, but is great for hand
>> encoders, AKA jog dials or MPGs (Manual Pulse generators).
>>
>> The problem I worry about is losing counts when moving slowly. Low cost
>> mechanical encoders and slightly more expensive optical encoders are
>> available in that and better resolutions for about $10. These generate
>> clean
>> quadrature pulses at TTL levels all in one piece, without any added
>> electronics.
>>
>> Jon
>>
>>
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