Re: Gecko minimum encoder specifications.

Erik

A motor driven with the 3xx series will always dither between two
adjacent encoder steps. As the steps get larger, you will get more speed
and overshoot as it dithers.

IMHO - If you place mechanical components between the motor and the
encoder in this arrangement, that dither will be multiplied by the lash
in the mechanical parts.

One of the stepper motion drivers in the EMC (smdromod.o) will allow you
to feed back pulses into the PC using the Kulaga/Mauch dro board. You
might consider using one fairly high res encoder on the motor shaft to
satisify the 3xx and the linears to feed actual position into the PC.

Ray

>    From: "Erik Reikes" <ereikes@...>

> What adverse effect would using an encoder with a smaller resolution
> than stated in the Gecko G320 manual have on its operation?  Has
> anyone tried using a G320 with a servo with less than 200 steps per
> rev (800 in quadrature)?
>
> The only thing that I can think of is that the PID loop might become
> so severely underdamped due to lack of feedback that it could dither
> like crazy between widely spaced lines on the encoder.