Re: Low cost Servo Controller

Les Watts wrote:

> I suspect EMC with the STG card will outperform LM628/9 systems which is why i'm here. The
> big cnc router I am building uses very high feed rates and following error is a big issue.

With the feedforward terms in the EMC motion control section, I think you can get following error
VERY close to zero. I got it so low, that I just stopped tinkering with it. Staying within a few thousanths
of an inch all the way up to 100 IPM, including the acceleration ramp was good enough at the time!

> I have a comment on the servo power amp-
> About a year ago I designed and built a large analog power amp (current limit is set at 20 amps!)
> and it took a month of weekends to get it going. But companies like Copley Controls sell a 12 amp
> h-bridge pwm amp for about $275. They will accept analog or pwm input I believe. I think I will just
> buy them rather than roll my own.

Well, Copely's prices must have come WAY down, or you have a special deal with them. The prices
I remember seeing are quite a bit higher that that. (But, I admit, they've been coming out with new
models quite regularly.)

> It makes more sense for me to be doing things like ball screw end machining right now.

Just don't do like me, and cut the precision ball screw an inch too short! Arrgh!
(I was able to use it, but it took a lot of head scratching to make it still work.)

Jon