Re: Slight Servo Problem

> No. He has the standard 500 cycle encoders, which provide 2000

counts

> in quadrature. So, that would be 360/2000 = .18 degree per count.
> Very interesting that you see such a difference. What motors are
> you using?

The Ametek motors have high resistance, and that makes

> me think they may have very high inductance, too! It may be that

the

> motor inductance is so high that it kills the control laws built

into the

> gecko drive, and the rapidly oscillating motor current acts to

defeat

> the integral windup that is supposed to happen.
>
> Do you have external capacitors connected right at the Gecko power
> input terminals? I put one on my client's system, and it seemed to
> improve the stability and stiffness, but I didn't have much time to
> investigate before the cap blew up (I had it wired backwards).
>
> Jon

I'm using Electrocraft E543 motors. They have a resistance of about
1.6 ohms which is much lower than the ametek if I remember correct.
I'm sure the ameteks do have a very high inductance, but I dont know
enough about electronics to know if that would cause a problem. My
encoders are 250cpr or 1000 pulses. Maybe a little to me is alot to
you, but they do seem very stiff. I guess the resistance/inductance
could cause it.

I'm not using a cap across the terminals, but the drives are very
close (maybe 12-14") to the supply which has 8, 100v 4700uf caps in
parallel.

Mark