Re: These servo motors worth a darn?

> From: "Marshall Pharoah" <pharoahm@...>
>
> I've been looking at building the DRO using Digital Research mylar strips,
> with an eye towards later on adding either steppers or servos. Am I
> heading down the wrong route?

It may not be the most efficient road, but I wouldn't call it wrong.
First, having the DRO itself is a big plus for computer 'assisted'
machining. I've done things using the computer for guidance and my
hands as the servos that would have required a tracer attachment to do
otherwise.

You may not be able to run a full closed-loop servo system using the
linear encoders, however if supported by software they could provide a
great 'missing step' detector for an otherwise open-loop stepper
system. And even in a servo system with rotary encoders, I could see
them being beneficial as a secondary confidence check. But again that
requires software support.

The biggest reason I think you should go ahead though is the
experience you will gain by figuring out how to mount the scales, wire
up the encoders, interface them to the computer, find or write
software, etc. All of that should come in usefull when you go for
full CNC.

Chris

PS - do you perhaps mean "US Digital" instead of "Digital Research"?
The former manufacture mylar strips for use with HP reader heads, I'm
not aware of the later being in the DRO business.

--
Christopher C. Stratton, stratton@...
Engineer, Instrument Maker & Horn Player
(978)538-5179 work, (617)492-3358 home
30 Griswold Street Cambridge, MA 02138
http://www.mdc.net/~stratton