On Tue, 10 Jan 2017, Gene Heskett wrote: > Date: Tue, 10 Jan 2017 21:39:09 -0500 > From: Gene Heskett <ghesk...@shentel.net> > Reply-To: "Enhanced Machine Controller (EMC)" > <emc-users@lists.sourceforge.net> > To: EMC <emc-users@lists.sourceforge.net> > Subject: [Emc-users] Two questions. > > Greetings all; > > I am up2date on the pi a/o this morning. So my first question is: > > Does the code I'm running have the latest commits from the work on the > encoder, or is that strictly benefitting the software stepping crowd? > > In any event, it seriously needs help. I hooked up the analog scope so I > could look at the waveforms and timings right out of the encoder, and > with the motor being driven at 60.8Hz, the waveforms are within 2% of > equal timings, and the overall speed wibblies are no worse than 2 or 3%, > with excellent quadrature. > > But if I hook up the halscope, the apparent quadrature error is worthless > due to the 1KHz servo-loop timing limiting the bandwidth. I may add a > bit of math to measure the loop time to see if there is something > usefull there, because while I am seeing at worst, a 4% time wobble on > the screen of my hitachi 1065, doing a capture with a minmax shows the > huge below figures. > > I fired up the minmax, set it for 60 hz, to the motor, reset the minmax > to start at a steady motor speed and at 30 minutes run time I had > logged a minimum of 269.9784 rpm's, and a maximum of 444.8399 rpms. No > way in hell the spindle speed was wobbling that much > > I left it running while I went out and rounded up some din-din and fed > us, but I must have had a blast of noise because after we had eaten, the > halmeters showed -1527449 rpms and 525176.6, so I have work to do yet on > the grounding. Humm, I can't recall if I put the vfd's control cable > ground under the ground bolt nut, or if it was just dropped over the > bolt, but I'd bet a cuppa caffeine its loose. First thing I check > tomorrow. > > Looking at the halscope, the 1khz sample is a mess. > > Is there a way I can process the velocity data by treating it to the time > between samples so its reduced if the last full cycle was longer, or > amplified if the last full cycle was shorter?, therefore leveling the > differences in velocity caused by the timing variations? Seeing a good > +-2% waveform on the analog scope while seeing a quad noise bar on the > halscope thats just short of 50% of the dc the noise is sitting on, says > the encoder signal from the 7i90 needs help, or the 7i90's encoder > itself needs help. > > How best to proceed? >
AFAIK there are no significant issues with HM2 encoder velocity estimation Heres a 100 Hz quadrature velocity trace: http://freeby.mesanet.com/100_Hz_quadrature_velocity.png Notice theres no discernible ripple in the velocity even though theres considerable sample jitter (green trace) (this config has a DPLL but its not being used to set the encoder sampling time) > 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> > > ------------------------------------------------------------------------------ > Developer Access Program for Intel Xeon Phi Processors > Access to Intel Xeon Phi processor-based developer platforms. > With one year of Intel Parallel Studio XE. > Training and support from Colfax. > Order your platform today. http://sdm.link/xeonphi > _______________________________________________ > 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. ------------------------------------------------------------------------------ Developer Access Program for Intel Xeon Phi Processors Access to Intel Xeon Phi processor-based developer platforms. With one year of Intel Parallel Studio XE. Training and support from Colfax. Order your platform today. http://sdm.link/xeonphi _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
