PIC-SERVO CNC controllers

I have been asked by a couple of members of this newsgroup to
elaborate a bit on the PIC-SERVO CNC control system described in a
recent Nuts & Volts Article, so here is a bit more information:

J.R. Kerr Automation Engineering is in the business of selling
PIC-SERVO motor control boards and PIC-SERVO motor control chip sets.
We have recently introduced a new product, the PIC-SERVO CMC (CMC
stands for Coordinated Motion Control). The coordinated control
features make it possible for non-realtime programs (like those
running under Windows) to generate precise coordinated motion of
several motors.

To help illustrate the use of this powerful new control feature, we
implemented a simple Windows-based CNC control program (PSCNC.EXE) as
an example for people to play with. Both the program and its source
code are being freely distributed to 1) clever individuals wishing to
"roll their own" CNC control systems, and to 2) developers looking
for
a starting point in implementing their own CNC or other coordinated
motion control products using the new PIC-SERVO CMC.

One thing I would like to stress is that we are a motor controls
company and not CNC experts. We are happy to support the products
that we sell, but the PSCNC example program is exactly that, an
example which you are free to use and modify, but that we do not
support. We also do not sell any CNC retrofit kits - you are pretty
much on your own on putting a system together. In the long run, we
would like CNC retrofit companies to offer support for the PIC-SERVO
CMC, but until then, we are happy to provide individuals with this
simple example to help put together their own custom systems.

All that said, a bit about the program itself:

There are two main advantages that the PIC-SERVO CMC has over
existing
retrofits in the same price range:
1. Servo motors are used rather than steppers. Motions are faster,
there are no lost steps, there is no having one axis merrily moving
along while another axis has stalled. Motions are smoother. The
amplifiers run cooler. The positions are displayed real-time, even
when the servos are turned off.

2. The program runs under Windows, using familiar intuitive controls.

There are also a few other features, including a dynamic feed-rate
override and contouring options which are not available on some
lower-end systems.

Of course, the program also leaves a lot to be desired in terms of
G-Codes supported and things like relative moves, alternate
coordinate
systems and backlash compensation. A graphical diplay would also be
quite handy. I would be more than happy, however, to see someone
implement some of these features for fun or profit.

Jeffrey Kerr
J.R. Kerr Automation Engineering
www.jrkerr.com