Peter, just as the name of threads says, I am trying to tune servo motors, not steppers :) I just checked - the supply voltage is 27,9 VDC, because 7i39 drives have 28 VDC limit.
Ohh, and there is update: The motor that yesterday worked fine at 4000 mm/min, today is not working fine at that speed - it also stalls and starts oscillating at relatively high frequency... Just as the name of thread says - I have no idea wtf is wrong with this machine. I just remembered one thing that I had not mentioned, but which probably might make a difference - Keling servos are equipped with CUI AMT102 encoders. I recall that Jon Elson wrote some time ago that these encoders have a lag during change of acceleration, so I looked at that thread again. Is there anything I can do to confirm, if the encoders are the real problem of the instability of the feedback loop. Viesturs 2012/1/29 Peter Blodow <p.blo...@dreki.de>: > 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 ------------------------------------------------------------------------------ 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
