Gene, how do I speed up the servo loop to test your theory? I’ll try that before I perform surgery on the BOB. I also have another BOB I can try, but it requires 12-24v power in order to enable its inputs.
On Tue, May 5, 2020 at 5:07 PM Gene Heskett <ghesk...@shentel.net> wrote: > On Tuesday 05 May 2020 17:48:01 Dan Henderson wrote: > > > I have a PMDC motor I’ve scavenged along with the MC-2100 motor > > control from a treadmill rated for 1.5 hp @ 90 volts. I’ve been > > testing it with LinuxCNC v2.7.15 in a mock-up environment I built for > > testing. I’m able to control the spindle speed via PWM pulses to the > > controller (HD2 pin 4). M3 S500 will get me somewhere between 520 and > > 580 rpm. You can hear the motor whine fluctuating with the RPM. I’ve > > also installed a CUI ATM 10 encoder on the back and seem to have it > > working with both an index and phase A signal. I have the jumpers on > > it set to 200 PPR but it can go all the way to 2048. I’m using a cheap > > china 5 axis BOB connected via parallel cable. > > > > Does anybody have any idea why I’m get so much flux on the rpm? Surely > > this isn’t normal? I know enough about the HAL to be dangerous. Is > > there some things I can check to smooth this out? Thanks. > > > If using a software encoder, as opposed to a mesa card, the time delay > between samples at the 1 kilohertz servo loop can do odd things. Among > others, the lag in the input opto-isolators of that bob can even cause > missed pulses from the encoder to the software. Try a much lower speed > to see if it stabilizes. If handy with a soldering iron, bypassing > those opto's can help, a lot. > > _______________________________________________ > > Emc-users mailing list > > Emc-users@lists.sourceforge.net > > 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 > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
