Re: Gecko minimum encoder specifications.

Hi,

We have run the G320 with encoders that range from 50 lines to 5,000
lines, the latter being a really fine Canon laser encoder. At the low
end the gain and damping has to be set relatively high.

If 50 lines is still to high of a line count, you can use the pulse
multiplier board (G902) that can bring the effective line count down
to 5 which should be enough; 2,000 steps per second would get you
6,000 RPM on the motor.

Mariss

--- In CAD_CAM_EDM_DRO@y..., Ray Henry <rehenry@u...> wrote:
>
> 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@r...>
>
> > 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.