Re: [CAD_CAM_EDM_DRO] Re: Re: Re: Can CNCPro users provide some input?

----- Original Message -----
From: dave engvall <dengvall@...>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Tuesday, March 20, 2001 5:18 PM
Subject: Re: [CAD_CAM_EDM_DRO] Re: Re: Re: Can CNCPro users provide some
input?


> Ray wrote:
>
> >
> > <snipped from Jon E>(and from Ray):
> > The advantage to a true velocity servo, straight from the computer, is
that
> > the VELOCITY is not quantized by the resolution. So, at very slow
speeds,
> > the motion remains smooth.
> > <eos>
>
> But this implies analog feedback via a tach. I suppose you could put a
tach on a stepper but the output would be almost as bad as
> an encoder. Maybe some kind of adaptive filter would fix that ...but I
thinking pure blue sky.
>
> >
> > And the 320 geckodrive has a max step rate around 250 Khz which would
mean
> > 60 RPM max on the encoder unit I have here. Nice resolution, but slow.
> > And EMC, at least isn't near ready to put out that many pps from a pure
> > software solution -- can't say about the other low cost cnc systems
>
> Well at that rate you'd get 1 KHz out of the encoder (at 250 ppr and
quad ).
> That doesn't scale too well at slow speeds.
>
> If Mariss goes purely distributor ( and you don't get grandfathered ) then
stepper systems get closer to servo's.
> Assembled amps (Copley ) are not too expensive and Jon's are somewhat less
but you get to assemble them.
> DC servo motors go from about $50 up on eBay. So the real expense is the
amp and the power supply.
> Just thinking out loud...which usually gets me in trouble.
>
> Jon makes a good case for servos but Mariss and others are doing a nice
job of supporting the stepper implementations. You pays
> your money and takes your choice. (Nomex suit on ). :-)
>
> Dave
>
>
> >
> >
> > Ray
> >
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> Welcome to CAD_CAM_EDM_DRO@...,an unmoderated list for the
discussion of shop built systems, for CAD, CAM, EDM, and DRO.
>
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> bill,
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>
> FAQ: http://www.ktmarketing.com/faq.html
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