RE: [CAD_CAM_EDM_DRO] First note-Help

I will second the recommendation of going with Gecko G3X0 step and direction
servo drives if you have not purchased anything for steppers yet. While Tom
is suggesting G340's my preference is to go with G320 and select the
encoders to give 6,000 - 10,000 steps per inch. The only difference between
the G320 and the G340 is the latter has an additional plug in board that
allows you to "multiply" you incoming pulses to drive servo setups that
require very high steps per second. Helps to take the stress off the
computer, but you can accomplish the same thing by selecting appropriate
encoder counts. The G320 is US$30.00 cheaper per axis that a G340. I have
G320's on my Shoptask and am in the process of setting up Bridgett (a
Bridgeport series II) with G320's. I love them and feel there is no
comparison to a stepper.

I would also give an endorsement for US Digital ( www.usdigital.com ). Nice
products, reasonable prices and super to deal with. For motors I have been
very successful picking them up on E-bay.


Tom,
How did you avoid electrical noise interfering with the encoder? I seem to
be having some problem with that and just got some National DS9638 & DS9637
differential driver and receivers to eliminate the problem. Regarding the
9638/9637 can any of you electronic gurus help me with a circuit diagram to
interface them with the encoders, the G320's, and an external power supply?
Don't want to tap the power off the G320 encoder power taps as I am sure the
current draw is beyond the Gecko spec.

Tim
[Denver, CO]

> -----Original Message-----
> I'll throw in my recommendation that you get some Gecko 340s
> and find some
> servo motors and skip the steppers, if you haven't already
> started down that
> road. The Geckos really only have two adjustments to make, Gain and
> Damping, and you can tinker with them and get them running
> pretty well. The
> limit pot adjustment is no big deal. I think CNC pro is
> very popular on
> this list, and many others will suggest their favorite cad
> /cam software.
> Yesterday, I just finished retrofitting a series I Bridgeport
> mill with the
> Geckos, and I love them for their simplicity. US digital has
> cheap encoders
> too. Just watch out for electrical noise interfering with the encoder
> wiring. Tim is also in the process of retrofitting a big
> Bridgeport mill.
> Get a catalog from US Digital on their encoder products.
> Their encoders
> will fit many shaft sizes.
>
> Others may suggest servo motor sources.
>
> Tom Eldredge
> >
> > Addresses:
> > FAQ: http://www.ktmarketing.com/faq.html
> > FILES: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO/files/