RE: [CAD_CAM_EDM_DRO] Re: G320s, New and Improved!

I just got an opportunity to test out the new and improved G320 drives on
Bridgett ( for you new comers that is my Bridgeport series II mill). I am
IMPRESSED!

First off there is virtually no dither noise. I do have one axis that you
can hear the motor shift back and forth very slightly and at a very slow
rate (maybe one or two cycles per second) when it is stopped in certain
positions. There is absolutely no humming noise that I used to get on the
old G320's.

Next up, the problem I had with interference is gone. Previously if I put a
dial indicator on the table and against the spindle and made a series of
.100" jogs I would get measured movements of anywhere from .096" to .104".
No particular pattern to the discrepancy. Prior to putting the recommended
caps on the encoder power leads it was worse with virtually all moves being
other than the desired .100". Also on the X axis particularly it would be
moving smoothly in a continuous move and then you would feel the axis jump.
Now with the new version of the drives every jog of .100" is exactly .100"
on the indicator. Moves on the X axis are smooth as silk without a single
jump or lurch.

Finally, the new drives don't have the 5 second delay to initialize. Flip on
the power and they come right online.

I have always been impressed with the G320 units. My first experience was
with a pre-production beta that Mariss offered to us on the list. They
worked great and were such an improvement over the steppers I previously had
on my Shoptask. This newest rendition makes them even better. With the new
anti-dither circuitry that Mariss has cooked up you can really crank up the
gain and dampening and get a much stiffer servo without the noise and motor
heating that would happen previously. The new interference rejection circuit
makes it so that the long (about 15') encoder cables are not a problem. For
anyone that has not already invested in steppers I would seriously recommend
you take a look at using servos with the G320/340 drivers instead.

Tim
[Denver, CO]