Slowing things down had marginal effect. Okay sounds like I need to by pass the optocouplers. Would you recommend I bypass all the encoder inputs as well as the PWM output to the MC2100 controller?
On Tue, May 5, 2020 at 6:34 PM Gene Heskett <ghesk...@shentel.net> wrote: > On Tuesday 05 May 2020 18:30:42 Dan Henderson wrote: > > > 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. > > > I meant slow the motor to see if it stabilizes, at say 75 rpm. zero > everthing at the pid except some FF0. > > Bobs nearly all have opto inputs, the only exception I know of is a long > discontinued cncv4pc C1G rev 4 board. Great board, but $80someting back > in the day. Many even have opto outputs. Mesa cards generally have > neither so they can work at 100x higher frequencies. The SainSmart bob > has no opto's in its outputs, but does have them in its 5 inputs. When > its being used with a Mesa 5i25, its totally comfortable with 200+ > kilohertz signals from a high res encoder, once those opto's are > bypassed. Without the bypass it only worked up to about 375 rpm at the > motor, then the opto's failed and the pid and motor went wide open. > > > 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 > > > 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
