This is not LCNC specif, but just motion control... Many times the secret is to do the homing twice. Once at full speed and as you note it overshoots. Then backup up until you bump the switch again then finally move as you say as 0.1 degrees per second. You don't need to actually stop at the home, just note the encoder count as you pass as the switch trips
Look at you 3D printer for inspiration. I think it goes fst to get a rough-homethen hits it slow a few times to take an average. Also for a rotary table I wonder if you could use a push button on a control pannel. You define home to be whatever you want. For example if you need to make 20 cuts to cut a gear, do you care where the firth tooth is on the black? On Thu, Dec 17, 2020 at 11:37 PM Gene Heskett <ghesk...@shentel.net> wrote: > On Thursday 17 December 2020 12:07:32 Gene Heskett wrote: > > > Greetings all; > > > > I have it working fairly well but had to restrict the cruising speed > > and accells to get the following error under control, not enough > > headroom in the supply or controller to do any better. Setting those > > down to 25 and 120 pretty well got rid of the big swings at start and > > stop, now staying within 5 millivolts on the halscope. It seem it > > needs the headroom of cruising at around 60% pwm duty to get up to > > speed and stopped again without lots of ringing at the start/stop > > points, and its stopping just prior to perfect balance from either > > direction, like .002 degrees or less despite a pretty aggressive Igain > > which some have used to get it to stop in the deadband. At a MAXVEL of > > 30 degrees/sec there is an occasional hint of windup, and MAX_ACCEL > > above 120 makes a big bump getting started and rings like a bell > > stopping, 25 and 120 make it behave really well. To improve on that, > > I'd have to use one of Jons pwm-servos, powered by the spindle psu at > > 125 volts. I'd like to see it turn faster, but at what cost? Its a > > 24 volt motor. Pix in a day or so when I get it reassembled and ready > > to rock and roll. > > > > Cheers, Gene Heskett > > One last problem. Ballistics before its homed may prevent homing, the > accel is very slow, at least 5 seconds to get up to cruising speed and > it winds up and coasts for several seconds after finger lift. so by the > time it finds the home switch it will have coasted many degrees past it. > > This is NOT how it acts after being homed wherever it is by all zeros in > the ini file. Then its moving and stopping according to the A settings > in the ini file, which are 25 degrees cruising and 120 accel. > > What do I set in the ini file that will give it close to the same > ballistics it has after homing? Or am I stuck searching for the home > switch at 0.125 degrees/sec or less? That would be beyond boring if it > was 1 degree beyond the switch and had to move 358 degrees to find it > again. > > Thanks all. > > Cheers, Gene Heskett > -- > "There are four boxes to be used in defense of liberty: > soap, ballot, jury, and ammo. Please use in that order." > -Ed Howdershelt (Author) > If we desire respect for the law, we must first make the law respectable. > - Louis D. Brandeis > Genes Web page <http://geneslinuxbox.net:6309/gene> > > > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > -- Chris Albertson Redondo Beach, California _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
