Thanks again, sir :) Phil T. The Feral Engineer
Check out my LinuxCNC tutorials, machine builds and other antics at www.youtube.com/c/theferalengineer On Fri, Mar 5, 2021, 10:38 PM Gene Heskett <[email protected]> wrote: > On Friday 05 March 2021 21:17:12 Feral Engineer wrote: > > > Thanks Gene > > > > My emco is running a pi 4 as well. Model b, 4gb. What kind of latency > > figures are you getting on your servo thread? I find mine to be a bit > > finicky unless I keep wifi off > > About 12 u-s. Worst I ever recorded was 200 u-s after pokig around the > planet with firefox for about an hour. But that is not as important as > you might think as both x and z are now 3 phase stepper servo's so they > haven't much to worry about even with bad latency because of the rubber > between the stepper drivers, which are in the mesa 7i90HD interface > card. So the servos are the coupling between the stepper driver and the > stepper itself. The advantage is that it only uses enough amps from the > supply to keep it running smoothly. So the steppers run zombie cool, and > with near total silence. Watching it run a program is a bit like > watching Casper The Ghost, its so quiet. > > I acquired this lathe with a broken compound, it fell over long before I > got it and landed on the compound crank, bending the spindle a few thou > from the sudden stop with a bison 3 jaw chuck mounted, which I've since > reground and it all runs true now. So now a QCTP is sitting on a couple > pounds of cast iron. I cut from the sprue of a white truck wheel, we > make them here in Weston, holding the TP a its normal height. It is so > solid there's very little tool chatter either. I don't miss the compound > since Linuxcnc IS a better compound than it ever had, doing far more > accurate angles. > > > Phil T. > > The Feral Engineer > > > > Check out my LinuxCNC tutorials, machine builds and other antics at > > www.youtube.com/c/theferalengineer > > > I've seen 3 or 4 of them. Decent stuff, > > > On Fri, Mar 5, 2021, 7:56 PM Gene Heskett <[email protected]> wrote: > > > On Friday 05 March 2021 18:35:19 andy pugh wrote: > > > > On Fri, 5 Mar 2021 at 23:31, Feral Engineer > > > > > > <[email protected]> wrote: > > > > > Can someone send me a copypasta of their spindle hal stuff? Pid, > > > > > ff0,1,2 encoder feedback, all that? > > > > > > > > I don't actually run PID on my lathe spindle. I have some > > > > moderately complex gear selection stuff going on, but otherwise I > > > > just trust the VFD to do the job. > > > > > > I don't have a pid loaded in either of my machines that are running > > > a vfd. The vfd is stiff enough it doesn't need fawncy controls. > > > > > > The only reason I have an encoder on the sheldon lathe is for G33.1 > > > and G76 support. Both of those slave the z travel to the spindle, > > > what ever its running at doesn't change more than 2% under cutting > > > load for G76, and maybe 5% for a big tap doing rigid taping. G76 > > > also slaves the x to the programmed G76 cutting depth. On the > > > sheldon, a pwmgen feeds a spinx1 which controls the vfd. Not even an > > > d/a except the spinx1 because I run the pwmgen at a rate thats above > > > the bandwidth of the spinx1. > > > > > > You get far better results by properly tuning the vfd. OOTB they > > > suck huge dead toads thru soda straws. With a pwmgen getting the > > > speed signals from motions spindle output, that pwm fed to the > > > spinx1 along with the dir signal, and a bit of hal sequencing, my > > > Sheldon, turning at 100 revs in high backgear, and low belt > > > position/speed, I can do a rigid tap move, and measuring the > > > overshoot at the bottom of the G33.1 move, is .25 turns. That's > > > with a nearly 40 lb 8" 4 jaw chuck mounted. Who needs a pid? > > > > > > That .hal file is attached. Cherry pick with my blessing. Sure its > > > a rpi4 file, but its running a Sheldon lathe that after stripping > > > the stuff linuxcnc doesn't need, and putting in decent ball screws, > > > still weighs around 1350 lbs. > > > > > > Stay safe and well, John. > > > > > > 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 > > > [email protected] > > > https://lists.sourceforge.net/lists/listinfo/emc-users > > > > _______________________________________________ > > Emc-users mailing list > > [email protected] > > https://lists.sourceforge.net/lists/listinfo/emc-users > > > 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 > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users > _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
