Re: [CAD_CAM_EDM_DRO] running the BDI EMC on a real machine

Les,

I'm running a BDI 2.04 (& various small modifications) with a servo setup
on a retrofitted Bport1 Moog. Drives/motors are Emerson FX/DX490's, and I
use the STGII card with feedback from US Digital E5D encoders mounted on the
ball screw ends. I'm pleased with it's performance, no motion control
problems.
EMC has quirks, but not in the servo motion/trajectory use. IO and
operator/G-code differences are the main things that require getting used
to. Currently the STGII IO is not used beyond axis limit, axis home, and
e-stop switches.
I'd recommend getting the 50pin IDC cable connector breakout boards for
the connecting the STG to amps, etc. The flat cable was not fun to solder to
the 25pin serial style connectors I used.
I also highly recommend getting the differential line driver encoders,
I've had zero problems with them (STGII takes differential encoder input) In
setup I crashed an axis at close to 600ipm, and the STGII/EMC combo didn't
lose encoder counts/position. Most problems I had/have were not with EMC at
all. Time from start (iron, STGII card, computer) to workable
(retrofitted mechanics, EMC 3-axis servo control) was about 6mo.
The block processing has a noticable delay before motion starts. (using
a P166 with 64mb is the main reason...) It does take some time to get the
EMC setup parameters figured out.
Performance-wise, the FX drives have a 3ms analog command delay. This
has kept the IPM lower than the motors are capable of. (by requiring the
following error values in EMC to be raised beyond acceptable accuracy.)

- Keith Rumley

> Well, I got no replies as far as people actually cutting material
> on a machine using the BDI EMC with servos rather than stepper mode. Frank
> mentioned he is using it to spit out
> stepper pulses to a Gecko as are others I think.
>
> Looks like I may be the first to try if I order the STG II card
> tommorow?
>
> Les
>
> Leslie Watts
> L M Watts Furniture
> Tiger, Georgia USA
> http://www.rabun.net/~leswatts/wattsfurniturewp.html
>
>
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