Re: List question

Ted wrote:

> From: "Ted" <rtr@...>
>
> rtr@...
> maybe I'm missing something, but integrating the movements of a couple of
> axes is what Bresham's Algorithms in linear and circular motion is about.
> It breaks down the motion into a lot of very small motions and steps the
> control through these small motions. It never allows the axes to loose
> synchronization by more than the resoplution of the machine, if you choose
> to limit the small motions to that size.

Oh, yes, of course. But, that is to be run on a single processor. You
can't have two separate processors each running part of the Bresenham
algorithms. So, a distributed system would run the Bresenham circle
generator, for instance, and send a stream of small, incremental moves
to 2 axis control processors. What if those axis processors get out of
sync by a few of those incremental moves? How does the central
computer keep them in sync? It can be done, but it is a lot more
complicated than just throwing the move commands down a blind
pipeline, and hoping everyone is on the corresponding move
simultaneously.

As for resolution, my machine has resolution of .00005" in the X and Y,
and .000025" in the Z. If I was moving X at 120 IPM (= 2 IPS), that
is 20,000 incremental moves per second, which is beyond the
capability of most systems to handle giving 3 (or more) axes
their marching instructions that fast. So, this sceme is really not practical
for systems that have a relatively fast motion capability.

Jon