On Tuesday 01 August 2017 17:17:39 andy pugh wrote: > On 1 August 2017 at 21:56, Gene Heskett <ghesk...@shentel.net> wrote: > > I could take the filter out, but I'd have to reduce Pgain by at > > least 75% just to keep it from hammering the gears in the head from > > the perceived errors in the velocity signal caused by a 5% > > quadrature timing error wobble in a 4 step repeatable sequence. > > You could feed the filtered signal to the PID and the unfiltered > signal to motion.spindle-revs. > Thanks Andy, and done. Now to see if it taps a better thread the next time. And if my eyes can tell the diff in terms of a cleaner tap.
> Though I am not sure that you want _any_ P in a closed-loop spindle. > But then both my machines run the spindle-speed open loop. (both have > more than adequate power, though). And no doubt, 3 phase motors and vfd's. This is a DC motor, running on a huge psu and one of Jon Elsons pwm-servo amplifiers. It takes a PID set good and stiff to match a 3ph and a vfd. When I said it was in trouble, starting at the top of a hole at 250 revs, when it finally gets to the last of the main tap stroke, its down to about 75 revs. I have Jon's amp set to limit the amps at around 15 and I can hear the squeak when it limits. Its a 90 volt rated motor, just a hair under 10 amps on the nameplate using its OEM scr/triac driver which is in a junkbox someplace. This supply sits at 126 volts, so I would think it should act like pretty close to 2 hp if running at its nameplate revs. Its not of course at the 250 revs in low gear. The head is full of vfx quality bearings so you just know the balls are well flattened and the ball cages are well eaten up by now. Theres no mistaking that sound. TANSTAAFL and all that implies and I'm well aware of it. But I have fun trying to make this pigs ear look like a silk purse anyway ;-) Ditto with this Sheldon. I just found this afternoon that the tailstock barrel has been invisibly smashed so the big end of the m2 taper is about 6 thou out of round! I have it chucked, and the tap-tru knocked down to around 2 thou, and a dial finger stuck into it says its around 7 thou out of round, with one high spot about 15 degrees wide. I am about to look up the m2 taper rate and take after it with an inserted boring bar since a wooden dowel at about that angle might be 2 days, and 50 recoats with a fine grade compound to get it down to a .002" runout. Then to add insult to that disappointment, 2 of the cheap live centers I just bought new, run perfectly true, but not to the m2 tail they have by about 20 thou. All of which can be fixed, but I'd like to have old meat in the pot ready for some target practice in time for the season this fall, and this is not making any progress on that front. :( I get the remains of a tooth extracted tomorrow, no clue when a new post can be put in so there goes at least 2 more days. Thanks Andy. 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> ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
