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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