Re: [CAD_CAM_EDM_DRO] question for potential Gecko 320/340 users

Steve Stallings wrote:

> I am in the process of finalizing the design for an
> interface board that provides, among other things,
> an isolated, buffered feedback from the Gecko 320/340
> step-servo drivers. Since this signal is different
> from other feedback and cannot be interchanged with
> plain contact closure inputs, where should it show
> up on the parallel port?

You're talking about position feedback from the encoders
to the CNC computer? You really can't do this with just a
parallel port. When the encoders are changing at a rate
of 40,000 counts/second or more, there's no way the CPU can
follow it without missing counts. You need to have hardware
counters there to make sure that every encoder count is
correctly counted up.

> It would be useful to hear from users of EMC, Master5,
> TurboCNC, CNCPro, MaxNC, and any other systems. If
> you prefer, or if you have trouble posting to Yahoo,
> you can reply to stevesng (at) newsguy (dot) com.

EMC uses the Servo to go board, or the Dan Mauch DRO
board, or my PPMC encoder counter board for this function.
All of them have some form of 24-bit bi-directional counter
with quadrature decoding dedicated to each axis.

Jon