Considering new servo product!

Hello, all,

After corresponding with John Kasunich about PWM and servo amplifiers,
an idea ocurred to me. I can make a modification to my existing Universal
Stepper Controller board (entirely by changing the configuration PROM)
that will make it put out PWM and direction instead of step and direction.
I could make a very simple servo amp that takes in PWM signals, and doesn't
have much smarts other than current limit and fault trip. This should be
pretty cheap to make. If I can do enough with the PID parameters in
EMC to get good response and stability, this should make a VERY simple
and cheap closed-loop servo system. And, if I can do DC brush motors,
I could then expand it to permanent magnet brushless motors (often
called DC brushless) too. That would cost 2 more power transistors,
one more half-bridge driver, and a few CMOS chips.

This DOES give up some smoothness at the very low speed end, and could
run into trouble if there is a lot of spring in a thin leadscrew or some
other
mechanical pole in the response. But, it should work as well as a Gecko
320, since that is what they are doing in hardware. Plus, all the
parameters
will be accessible from software. It also makes it possible to go to higher
voltages and currents than the Gecko can handle.

This would also allow me to offer a complete package all from one source,
and to offer kits (all the complete and tested boards, no box or power
supply)
as well as complete NC driver boxes.

Any comments?

Jon