Nice. That video was a year ago. I know the machinekit port for the beagle is much older than that. I don't know why it wasn't dealt with. I assumed for some reason there's an issue that makes it complicated. Perhaps, and this is only a guess, only one QEP is available with the HDMI enabled. Pin wise. And if that's the case the need for an MPG on a pendant was considered more important.
The MPG on my ELS has 16 positions. That turns out to be plenty for sneaking up to a point or moving the axis a bit to shave off a tiny bit more. And it's dealt with in software inside the 20kHz interrupt routine. No QEP hardware needed. Plus the encoder closes a contact when the shaft is pressed downward. That brings up a menu to let you changed from 0.001" per click up to 0.020" per click (or metric if you are in that mode). So maybe software reading two hardware inputs for an MPG on a pendant and the QEP hardware for the spindle and then encoder threading with the beagle is possible. John > -----Original Message----- > From: sam sokolik [mailto:sa...@empirescreen.com] > Sent: October-13-17 6:07 PM > To: emc-users@lists.sourceforge.net > Subject: Re: [Emc-users] MachineKit on the BeagleBone Black > > Pathpilot does not work out of the box. (Unless you have a tormach or a > machine setup exactly like a tormach..)� If anything it is harder to > configure than linuxcnc.� It isn't meant to be.� It is missing stuff > that normal linuxcnc has. > > There seems to be a very warped view of linuxcnc.� memories of olden > days.� Linuxcnc is hard they say.�� You have to know linux to run > linuxcnc.�� You have to be a programmer to use linuxcnc.�� That hasn't > been true for a long time. > > Linuxcnc isn't that hard to setup.� You just have to invest a minimal > amount of time to understand it. > > and yes - single pulse threading does work with linuxcnc > > https://www.youtube.com/watch?v=jHKmcjoCyLg&t=50s > > sam > > On 10/13/2017 07:57 PM, Chris Albertson wrote: > > Andy, > > > > Of course one pulse per revolution can work. Those who argue it can't are > > likely not > > thinking how to compute shaft velocity. Still, you get a tighter loop with > > more pulses per revolution > > and as Gene wrote, it is not hard to make an encoder. > > > > Thanks for the hexagonal boring video. I would have never guessed this > > could be > > done so easy. Now of course I have a use for it and "need" the feature. > > I'd been > > connecting motor shafts to aluminum parts using round holes and set > > screws. Now > > I see I can bore a "D" shape with will ft the flat on the motor shaft. > > > > > > > > On Fri, Oct 13, 2017 at 5:40 PM, Gene Heskett <ghesk...@shentel.net> > wrote: > > > >> On Friday 13 October 2017 18:21:15 andy pugh wrote: > >> > >>> On 13 October 2017 at 23:13, John Dammeyer <jo...@autoartisans.com> > >> wrote: > >>>> The desire for the Beagle with me was originally that with LinuxCNC > >>>> and a quadrature encoder on the spindle along with the hardware QEP > >>>> handled by the PRU we'd have an awesome little lathe controller. > >>>> Alas, that's the one thing in MachineKit that hasn't been addressed > >>>> yet. > >>> I lost track of Machinekit a while ago. Do they have any > >>> encoder-counting facility in the PRU? > >>> > >>> If they have then the rest is just config. (editing text files...) > >>> > >>>> Mach3 and my ELS both use one pulse per revolution for threading. > >>>> And before this starts a massive thread on how that just can't work, > >>>> it does work and as long as the spindle is reasonably steady it > >>>> works well. > >>> Indeed, and LinuxCNC can be persuaded to work that way too. > >>> > >>>> But you obviously can't just stop the spindle mid thread and then > >>>> turn the spindle by hand manually. So there are limitations. > >>> LinuxCNC can do this (and yes, I am turning the spindle by hand): > >>> https://www.youtube.com/watch?v=T4q8gCpeY1A > >> You can also rigid tap that way, by turning off the spindle power once > >> the G33.1 has started, I have done it on TLM, easy because its spindle > >> has AC ball bearings. Weird feeling to watch the carriage following the > >> encoder, while you are turning the spindle by hand, in either direction. > >> I've now built 3 encoders from scratch, all with 240 or more A/B edges > >> per revolution. Usually works a treat. Or tells one quickly that its > >> screwed up. > >> > >> 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) > >> Genes Web page <http://geneslinuxbox.net:6309/gene> > >> > >> ------------------------------------------------------------ > >> ------------------ > >> 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 > >> > > > > > > > ------------------------------------------------------------------------------ > 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 ------------------------------------------------------------------------------ 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
