Re: [CAD_CAM_EDM_DRO] EMC-installation

["Joel Jacobs" <jj-at-netexp.net>]

----- Original Message -----
From: "Clint Bach" <clintbach-at-earthlink.net>
To: "Multiple recipients of list" <emc-at-nist.gov>
Sent: Friday, April 07, 2000 1:29 PM
Subject: Re: [CAD_CAM_EDM_DRO] EMC-installation


>
> BTW, I'm using steppermod instead of freqmod because I get following
> errors at anything over 0.6 jog rates. I could probably figure that one
> out with the .ini file.
>
How fast do you need to jog?  .6 is 36 inches/min!  I would suggest you
chuck steppermod and spend whatever time you need to get freqmod working.
Aside from being much smoother, it may help your lost step problem.  I had
the same problem with mine and I had to re-program my controller to have
less latency reading the direction bit.  EMC outputs a valid direction bit
during a positive step edge.  The direction bit may change 1XPERIOD later
and if your controller has not responded yet it will step the wrong
direction.  steppermot doesn't use the PERIOD variable so If your controller
is too slow there's not much you can do.  If you are using freqmot just set
PERIOD > your controllers latency and that should solve the lost step
problem.  It's really hard to believe that a commercial controller is too
slow though.  You might check and make sure you have pull-ups on the
controller - should be around 4.7k.  Some bypass caps - about 470PF - at the
controller, would also help if it's a noise problem.
Good luck - it's quite nice after you get it working...

Joel