Re: [CAD_CAM_EDM_DRO] Re: Re: PIC-Servo

So you are saying you are using EMC to run a servo
without a step converter? PIC-Servos close the loop
on position and are controlled by position commands
via a serial line. The problem is to get EMC to
communicate via a serial line.
With the new CMC chipset that buffers position
commands it seems that all that is required is for EMC
to output packets with the desired positions for all
axes. Real-time output is not necessary since the
PIC-Servo buffers up a bunch of commands. Has this
type of communication been implemented in EMC?

--- Jon Elson <elson@...> wrote:

> >
> > > From: "andrew abken" <kn6za@...>
> > <s>
> > > I would trash this system If I could find a
> way to run emc with direct
> > > command control of servos, and do it on a hobby
> budget. I think some folks
> > > are very close to comming up with just such a
> system, but until then Ill
> > > keep making chips fly with pic-servos.
>
> Well, I've been doing it for several years. Maybe
> you'd better define your
> budget for us. For servos, you need not only motors
> but encoders. Careful
> searching of surplus sources can usually find
> encoders at a reasonable price.
> There are usually a few on eBay at any time.
>
> You need an encoder counter per axis so the computer
> can read the position,
> and you need servo amps and a way to command them.
> The old way was through
> +/- 10 V velocity command signals, so you need a DAC
> per axis to send those
> signals to the servo amps.
>
> Velocity servo amps need a way to sense axis
> velocity. The old way was through
> a DC tachometer, but many newer amps can use encoder
> signals.
>
> Copley controls has some fairly inexpensive servo
> amps in a range of sizes,
> but they are about twice as expensive as a Gecko
> drive, ie. around $200 ea.
>
> I've got all the rest of it in a 3 board set, see <
> http://pico-systems.com/PPMC.html >
> for more info.
>
> Jon
>
>
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