On Sat, 28 Jan 2012, Viesturs L?cis wrote: > Date: Sat, 28 Jan 2012 11:25:00 +0200 > From: "[UTF-8] Viesturs L?cis" <viesturs.la...@gmail.com> > Reply-To: "Enhanced Machine Controller (EMC)" > <emc-users@lists.sourceforge.net> > To: "Enhanced Machine Controller (EMC)" <emc-users@lists.sourceforge.net> > Subject: Re: [Emc-users] Servo tuning - wtf? > > Hello! > > I have spent some time with the machine and have tried some of the > suggestions. > > 2012/1/27 andy pugh <bodge...@gmail.com>: >> >> At that speed with a 2-pole motor a 1ms servo period ought to be OK, >> but you should try 500uS to see if that helps. >> > > This was the only thing that helped - I reduced servo period to 500 us > and the motor oscillation borderline shifted from 3660 mm/min to 5114 > mm/min. > Reducing servo period down to 250 us did not provide any additional > improvement. > >> >> What happens if you disconnect the PID (and the motors from the >> machine!) and setp bldc.0.value 0.95 ? >> > > I did the following: > # net motor.00.command pid.0.output => bldc.0.value > setp bldc.0.value 0.95 > > Result: nothing. Motor does not move. > > If I change back: > net motor.00.command pid.0.output => bldc.0.value > # setp bldc.0.value 0.95 > > Then I can jog motor. > > I tried 3 times switching back and forth - with PID disconected and > BLDC value set to 0,95 motor does not move.
Thats very strange, the motor should run at full speed with a fixed bldc drive value. Can you post your hal file somewhere (like pastebin.com) > > 2012/1/27 Peter C. Wallace <p...@mesanet.com>: >> >> So if you set the PID comps MAX_OUTPUT to 158 (and PWM scale is 166.67) that >> will limit maximum PWM to the desired 95% >> > > I reduced those values and also set max output to be less than 95% of > output scale: > OUTPUT_SCALE = 125 > OUTPUT_OFFSET = 0.0 > MAX_OUTPUT = 118 > > It did not provide any additional improvement. It would not provide any improvement, just prevent pathological behaviour if the PID sets the PWM to 100% (which should be prevented) > > So this far only reducing servo period did help. Unfortunately that is > coming with RTAI error warning messages. I ran latency test for a > while and got 12000 ns max jitter on servo thread. > > Viesturs Is this on a 5I23? 2 KHz should be easy (I am running a 8I20 test at 6 KHz currently with a 5I23) Do you have a base thread? (you shouldn't need one) > > ------------------------------------------------------------------------------ > 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 > Peter Wallace Mesa Electronics (\__/) (='.'=) This is Bunny. Copy and paste bunny into your (")_(") signature to help him gain world domination. ------------------------------------------------------------------------------ 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
