On Tuesday 15 March 2016 01:58:05 Kirk Wallace wrote: > On 03/14/2016 03:55 PM, Gene Heskett wrote: > > On Monday 14 March 2016 18:08:48 andy pugh wrote: > >> On 14 March 2016 at 21:58, Gene Heskett <ghesk...@wdtv.com> wrote: > >>>> Have you tried reversing without the relay? I don't have any > >>>> braking relays and my spindles all stop adequately quickly. > >>> > >>> The only relay present on the control board is apparently the > >>> external reverse signal. There is a page in the parameter menu > >>> that can switch that around some. > >> > >> Can I re-phrase the question with the word I meant to type? > >> > >> Have you tried reversing without the _resistor_ > > > > That is what I was trying to describe Andy, and I can reverse it > > from 6k rpms fwd to 6k rpms in reverse and back in 1 second total > > each way. No hits, no runs, and NO errors. I'll try it in even > > less time tomorrow. Once, from 100 rpms. it was so violent it > > uncrewed the collet nut! > > > > Cheers, Gene Heskett > > I didn't realize my dynamic braking wasn't working until I tried using > CSS (constant surface speed, G96, > http://linuxcnc.org/docs/2.7/html/gcode/g-code.html#gcode:g96-g97 ) > with my lathe. If your lathe can do CSS, you might want to include > this in your testing. My lathe was over-volting on a rapid move from 0 > radius (CSS set to 2500 RPM max.) to a 1 inch radius (a few hundred > RPM) during a facing routine. It seems that my VFD doesn't honor its > deceleration ramp register settings because the CSS deceleration is a > bunch of speed commands (, at the servo rate?, ) from LinuxCNC rather > than a single command to a new RPM which G97 RPM mode would use.
What type of interface Kirk? I intend to use a pwmgen, which would update its analog equ at the servo rate, normally at 1 KHz. If thats a problem, coming out from zero radius where the first 1/8 would be a pretty large & fast slowdown, I think I would look at it as a windup in the PID caused by the 2500 rev limit, and would try to apply the usual suspects fixes for a windup condition. I've had symptoms of that show up in my testing speed changes while looking for the best pid response, and had to reduce the IGain if the speed chnage commands were too close together in time. FWIW, at one point, experimentaly, I ran the servo thread at 4kilohertz on my toy (7x12) lathe, which stabilized it quite a bit, but it also made that D525MW motherboard work pretty hard. I did finally wind up back at 1KHz with some pid settings that were to me, pretty phenominally stiff. That was after I had cobbled up the hal stuff to use the weighted average of the last 4 encoder edges going by, cutting the cyclic encoder noise by a /4 factor. That helped considerably, so when I was configuring the .hal on the mill, I imported that glop of code and re-used it. The only time I've noted the mill slowing due to load was when trying to tap a 10mm hole with a g33.1 wrapped in a peck cycle. But to do that safely, I have got to figure out a way to get a better grip in the tap shank, it was slipping even with a 10" handle extension on the chuck key handle! But nobody seems to make one with a square drive. Theres a different std drive square size for every tap & no two tap makers use the same table. Another potential fix might be to use a lower maxvel for the x, its total range might be only 15% of the z travel. I've used css, but usually in terms of turning, as opposed to faceing. I find it isn't as easy to calibrate & use well unless the tool table is very accurate, something mine is not due to a lack of sufficient qc tool holders. Thats my fault of course and I get a couple more everytime I order parts from Larry, but I don't have half enough of those yet. 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> ------------------------------------------------------------------------------ Transform Data into Opportunity. Accelerate data analysis in your applications with Intel Data Analytics Acceleration Library. Click to learn more. http://pubads.g.doubleclick.net/gampad/clk?id=278785231&iu=/4140 _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
