RE: [CAD_CAM_EDM_DRO] Encoders on stepper motors.

Here is the concept.
The Gecko G3X0 series are closed loop between the driver and the motors, but
open loop between the computer and the driver.
EMC supports a closed loop stepper mode that outputs normal step and
direction signals and reads back the encoders to verify that the actual and
commanded positions match.
If the G3X0 is hooked up with the encoders also feeding to a Mauch/Kulaga
DRO card EMC would now be able to have a fully closed loop. It will speed up
the step rate if an axis is lagging until it hits the follow error threshold
(user configurable) and then it will abort the program if the threshold is
exceeded.
If this setup works successfully it would give all the functionality of a
true servo installation except for the velocity command. Everything would
continue to be positional and you would still have stair stepping at shallow
angles. Not perfect, but considering the G3X0 can be had for $100 - $130 per
axis right now and the DRO card is only $60 or so you can have all the
electronics for this in the $360 - $450 range. A motion control card is
currently $800 (Servo to Go) and you still need servo amps. Not a bad
compromise of it works.

Tim
[Denver, CO]

> Dan,
>
> Please comment on this configuration:
>
> EMC outputting step/direction, driving a gecko 340 drive,
> with the encoder
> feeding both the gecko drive and your emc/encoder feedback board.
>
> Thanks,
>
> Tom Eldredge
> >
> > FAQ: http://www.ktmarketing.com/faq.html
>