Even with the encoder scale set at 2000 and the near scale set to 1.3 I can't get spindle-at-speed to go true properly. Not sure what else is wrong, I'll have to double check the encoder. Closed loop would be nice as it would compensate for the probable gearing issue, though I could probably fix it for real by just turning a new motor pully on my manual lathe. I'm not sure how big a deal a 20% error is in the real world, I guess for some more exotic materials it could put the SFM out of the correct range.
At any rate, I'm getting ready to go out of town for three weeks, so I'm probably not going to have any more time to work on this until I get back. At least I can go away knowing that when I MDI S750 M03 it actually does it :) ------Original Mail------ From: "andy pugh" <[email protected]> To: "Enhanced Machine Controller (EMC)" <[email protected]> Sent: Fri, 19 Sep 2014 02:03:14 +0100 Subject: Re: [Emc-users] New to LinuxCNC and PnCConf and need some help... On 19 September 2014 01:29, <[email protected]> wrote: > More fiddling and it appears the encoder is 2000 CPR. 2000 is quite likely, as is 2048, you could try 10 turns to be sure. > I seem to recall there was a parameter somewhere for an analog output offset > that I could perhaps use The first thing to try would be to see if you can get it close by changing the OUTPUT_SCALE in the INI. Closed-loop is very much an option, I noticed that PNCConf has actually created a pid.s component, presumably with this in mind. divert the spindle-speed-rpm-abs signal to pid.s.command, then net pid.s.out to 5i25.....spinout and encoder.0.velocity to pid.s.feedback. You will probably find that the best pid scaling is an FF0 of 1, Pgain 0, Igain 0.05 (or some other small value) and Dgain 0. You may actually need to use the spindle-command-rps-abs pin to drive the pid if the encoder output is in rps. In that case an FF0 of 60 might be appropriate, or set the OUTPUT_SCALE to rps instead -- atp If you can't fix it, you don't own it. http://www.ifixit.com/Manifesto ------------------------------------------------------------------------------ Slashdot TV. Video for Nerds. Stuff that Matters. http://pubads.g.doubleclick.net/gampad/clk?id=160591471&iu=/4140/ostg.clktrk _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users ------------------------------------------------------------------------------ Slashdot TV. Video for Nerds. Stuff that Matters. http://pubads.g.doubleclick.net/gampad/clk?id=160591471&iu=/4140/ostg.clktrk _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
