Re: quadrature endcoder woes?

Hi Aaron

I'm glad to have helped once so for what it's worth here comes a
little more. I think the encoder you mentioned was 300 lines (1200
counts/rev). That's 6 counts on a typical 200 step motor so you
should use a driver with over 12 microsteps (realistically use 18-24
or more). If you can't position the motor 2x better then the encoder
can see and you use some kind of closed loop feedback looking at the
encoder you'll probably get an oscillator (big ringing that might not
stop, like the resonace band) at the end of each move.

Al

--- In CAD_CAM_EDM_DRO@yahoogroups.com, Aaron <aaron.groups@g...> wrote:
>
> eewizard_1 wrote:
>
> >Hi Aaron
> >
> >Is it a stepper motor and can you spin it a LOT faster? At 1RPM you
> >only get 3.3 full steps/sec on a 1.8 degree stepper motor and unless
> >you use a GOOD driver with a high microstep count you might be seeing
> >the motor cogging. I have seen that with low cost drives but with a
> >Compumotor drive/indexer that has 25000 steps/rev it goes away.
> >
> >Try 500 RPM and it may look like you expect.
> >
> >Al
> >
> >
> Thanks to everybody for their suggestions.
>
> As some suggested, I tried cleaning but the results were to no avail.
>
> The traces looked normal once I got above a couple hundred RPMs.
>
> In accordance to the suggestion above, I dug out an old API drive and
> set it up for 1/64 microstepping. At 1 rpm, the traces looked fine.
> The only irregularities I can now see is when I accelerate through the
> resonace band.
>
> Regards,
> Aaron
>