On Thursday 28 April 2016 19:38:19 Peter C. Wallace wrote: > On Thu, 28 Apr 2016, Gene Heskett wrote: > > Date: Thu, 28 Apr 2016 18:29:04 -0400 > > From: Gene Heskett <[email protected]> > > Reply-To: "Enhanced Machine Controller (EMC)" > > <[email protected]> > > To: "Enhanced Machine Controller (EMC)" > > <[email protected]> Subject: [Emc-users] New motor and > > driver in, runs w/o the springs, at 10% of the big motors noise, but > > no faster. > > > > Greetings; > > > > I can do 48.7 IPM all day, either direction, but one cliock faster > > on the jog speed, to 51 IPM and I have a following error in about > > 3/8" of movement, independant of the direction. Next step up on the > > slider is about 53.x IPM, gives a following error in about 3/16" of > > motion. > > > > The step timings are: > > dir preset 6000 > > Step_len 3000 > > Step_space 3000 > > dir hold, 6000 > > > > Worst case, 18 u-s to do a dir reverse and one step then revert the > > dir. 12 u-s for dir_setup+dir_hold, and 6 more for the step=18. > > > > Grabbing a copy of kcalc, enter 18 as .000018, do a 1/x to get the > > max freq=55,555.5555555555556 or a bit over 55 kilohertz. Drive > > claims it can do 200 kilohertz. driver is set for /8 microsrepping. > > Screw is a 16x5mm. > > > > So how fast can it go when the pulses are at 200 KHz? > > > > FWIW, this tripping of the following error was taking place at the > > exact same speed ( give or take a couple percent ) with the previous > > driver & motor which was set for a /64, and the same step timeings > > and this one is set /8, so no way can I convince myself the problem > > is the maximum step rate the 5i25's stepgen can do, or that the > > driver can eat and be happy. > > > > I have fiddled with the ini files maxvels, and maxaccels, without a > > measureable effect. > > Sounds like the stepgen maxvel or stepgen maxaccel settings are > limiting you, so you are getting a following error. With 3/3 usec step > timings you should get close to to 166 KHz. The stepgen maxaccel and > stepgen maxvel parameters should be set to about 1.25X the machine > acceleration and velocity limits > Would this be more related to the TP asking for a higher velocity?
> If you have backlash compensation enabled, the stepgen maxaccel > parameter must be set to about 2.5x the machine acceleration limit Playing last week, backlash is .0016", I found the stepgen_maxvel was best at around 1.35, and currently the max_accel is 10 while stepgen_maxaccel is about 35 setting max_accel to 20 and stepgen_maxaccel to 70 did not make an apparent difference other than the accel time almost vanished. I could not do that with the 1600oz/in motor, it would skip a step now and then, w/o stalling, at a maxaccel of 8 & stepgen_maxaccel of 24. Backlash is around .0016" and I can see teeny little spike of correction in the halscope. If its going to ring & trip out, the ringing starts later, during the constant velocity portion of the waveform I can trace with halscope. This is not a start of motion thing, its up and moving at a steady rate and has been singing the same tone for at least 3/4 second when it errors. > The 5I25 stepgens can do ~8 MHz step rate 40 x faster than this driver can do... But its been a long day for this old fart, so I'm going to catch some Z's, hoping I don't roll the left knee wrong like I did last night in the night. That can totally waste a perfectly good nights sleep. Thanks Peter. 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) Genes Web page <http://geneslinuxbox.net:6309/gene> ------------------------------------------------------------------------------ Find and fix application performance issues faster with Applications Manager Applications Manager provides deep performance insights into multiple tiers of your business applications. It resolves application problems quickly and reduces your MTTR. Get your free trial! https://ad.doubleclick.net/ddm/clk/302982198;130105516;z _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
