On Wed, 1 Feb 2017, Dan Bloomquist wrote: > Date: Wed, 1 Feb 2017 17:19:51 -0800 > From: Dan Bloomquist <z...@lakeweb.net> > Reply-To: "Enhanced Machine Controller (EMC)" > <emc-users@lists.sourceforge.net> > To: "Enhanced Machine Controller (EMC)" <emc-users@lists.sourceforge.net> > Subject: Re: [Emc-users] Eagle mill retro fit > > Peter C. Wallace wrote: >> <http://www.ebay.com/itm/Fenner-Servo-Dynamics-Servo-Amplifier-SDF1525-12-SDF152512-AS-IS-/151719664648?hash=item2353325c08:g:0xkAAOSwxYxU0lv4> >> >> >> >> https://forum.linuxcnc.org/30-cnc-machines/30032-servo-dynamics-brushed-dc-servo-sd1525-tuning >> >> >> >> The drives do have tachometer inputs (unless the SDF1525 is much >> different than the SD1525) > > Hi Peter, Andy, > I found that earlier and saved the pdf pages in case I would need them, > I did think until today they got speed feedback from the motors. But the > board's tach input have nothing plunged in, so zero and gain would be > the only meaningful adjustments. What you write Andy is talking me off > the ledge. I get the DC feedback, I was just surprised it was not > pulsed. I'm very green to a CNC machine of this class. So I don't see > the tachs being connected to the 7i77, it doesn't have analog inputs, > ADC, or there is another way? From your last paragraph, I can just go > glass into the 7i77 and it will deal with it? I've read that just glass > in is iffy, but I just don't know. > > Best, Dan. >
I think what may be confusing you is that its entirely possible to have the tachometer feedback connected at the controller and have the analog subtraction of commanded velocity (from motion commands) and feedback velocity (from the tachometer) done somewhere else other than at the drive inputs >> > > > ------------------------------------------------------------------------------ > Check out the vibrant tech community on one of the world's most > engaging tech sites, SlashDot.org! http://sdm.link/slashdot > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > Peter Wallace Mesa Electronics (\__/) (='.'=) This is Bunny. Copy and paste bunny into your (")_(") signature to help him gain world domination. ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, SlashDot.org! http://sdm.link/slashdot _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
