Re: Servo Amp designs

>
> From: Jon Elson <jmelson@...>
> paul@... wrote:
> > Using the PIC for interface as well, it gets driven through a
> > standard RS232 port using various commands (absolute or relative
> > moves, velocity, etc). The code incorporates a tunable PID
> > algorithm, velocity ramps, etc. Using a 16Mhz clock, it can
> > run a PID calculation every .25 milisecond.
>
> Ohh, there's the killer, right there. Just like all the other darn
> beautiful one-axis chips (Nat Semi LM628/629, HP HCTL1200
> etc.) when you need coordinated motion on 2 - n axes, it all falls
> apart. Especially for contouring or engraving, where you're following
> splines with a change in angle every few thousandths of an inch.
> That's the reason why everyone seems to come up with some way
> of using one processor to compute the trajectory for ALL the axes.

Good point; the appnote is really talking about a 1 axis solution.

--
Paul Amaranth | Rochester MI, USA
Aurora Group, Inc. | Software Development
paul@... | Unix / C / Tcl-Tk