Viesturs, regardless of possible tuning questions, if I recall right, you are using a 24 volts supply for the stepper amplifiers. This seems a little low to me as I was using 90 volts on my dual Parker Hannifing amplifier/driver. I had stepper motors attached to the two slides of my lathe and never experienced any oscillations. The amps came to a maximum of about 30 kHz, but as the steppers were coupled directly to the spindles (no gears) they reached the spindle ends before frequency could grow any higher anyway. The motors have about 85 mm diameter and are labelled for 3 volts so there is a lot of momentum in this drive. When a slide accidentally hit the physical end of a way (no limit switches there), it usually turned off the 3 mm steel dowel I am using in the couplings.
I think at your 24 volt level and the resulting maximum motor forces or angular momenta, you are working near the physical resonance limit where anything can happen. Try a higher power supply voltage in any case. Peter Viesturs La-cis schrieb: > 2012/1/28 Peter C. Wallace <p...@mesanet.com>: > >> OK so commutation is ok, but somthing is funny here. You said it oscillated >> even with a P of 1 and all else 0. Did it not oscillate with a P of 3? >> what is the difference between the setup now and when it oscillates? >> >> > > I will try to explain: > I am trying to tune 2 motors simultaneously, because it is a gantry machine. > So what I did few minutes ago: > For both motors: all PID parameters set to 0 > P = 3 > I tried to jog the gantry at slow speed. > At 240 mm/min it is smooth, at 480 mm/min still smooth, but at 676 > mm/min there are spots, when one of motors stalls and oscillates in > small amount at high frequency. I suspect that the stalling is due to > some uneven load to motor, when moving forward. > Anyway, I d not know, how to overcome such stalls and subsequent oscillation. > Hitting F2 to disable and re-enable motion stops oscillation and I can > jog forward. Until one of motors stalls and starts vibrating again. > > I do understand that final settings for both gantry motors might > differ, I just think that in the beginning they could be tuned > together as both of them are stalling now. > > Viesturs > > ------------------------------------------------------------------------------ > Try before you buy = See our experts in action! > The most comprehensive online learning library for Microsoft developers > is just $99.99! Visual Studio, SharePoint, SQL - plus HTML5, CSS3, MVC3, > Metro Style Apps, more. Free future releases when you subscribe now! > http://p.sf.net/sfu/learndevnow-dev2 > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > > ------------------------------------------------------------------------------ Try before you buy = See our experts in action! The most comprehensive online learning library for Microsoft developers is just $99.99! Visual Studio, SharePoint, SQL - plus HTML5, CSS3, MVC3, Metro Style Apps, more. Free future releases when you subscribe now! http://p.sf.net/sfu/learndevnow-dev2 _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
