Re: Homebrew STG card

["Ian Wright" <Ian-at-iw63.freeserve.co.uk>]

Hi,

----- Original Message -----
From: Jon Elson <jmelson-at-artsci.wustl.edu>
> I thought of one other use!  I have a mini-EDM setup, which is
> right now, open loop.  I'd like to have EMC (with some hacking)
> control feed rate by watching the EDM current, and varying speed
> to try to maintain constant current, but also being able to back off
> and start feeding again when a short ocurrs.  This wouldn't be
> too hard, but I think an analog input would make it a lot easier.

If someone could figure this out it would put us well on the way to being
able to build a wire EDM machine.  This is something I would very much like
to do and I know others on the list have expressed interest in such a
machine.  Presumably, you would use the current feedback (which would have
to be well smoothed and filtered to get rid of spark transients) to do a
kind of overall control on the feedrates of one or more axes (two in the
case of a wire EDM) and have EMC still do the maths to give the necessary
differential feedrates to follow the desired path.

Ian

--
Ian W. Wright
Sheffield  UK.