On Wednesday 06 May 2020 23:30:19 Gene Heskett wrote: > On Wednesday 06 May 2020 22:20:12 Dan Henderson wrote: > > I’ve confirmed the fluctuation occurs when spindle-at-speed is > > configured. When I remove this feature, the spindle rpm appears to > > stabilize. It’s almost like it gets caught in a loop trying to chase > > its tail. > > The clues would tend to point in the direction of the output of the > spindle-at-speed signal somehow getting into the feedback loop to > modify the feedback value. > Dan: Be aware if using master, that the syntax has changed, due to new multiple spindle control abilities LinuxCNC has grown, it is now spindle.N.at-speed, where for you with one spindle, N is 0. And I've some configs to fix too...
Did you find anything yet? > Check, and then recheck your hal file for some sort of coupling that's > probably unintended. Look at otherwise identical modules you've used > more than one of and make sure the unique marker such as an instance > number is correct, it could be a classic off by one typu. Such as > that will eat your lunch. In rare cases you may have to survey the > running system with "rockhopper", (google for it, pain in the butt to > use but its also very very good at what it does, which is to graphicly > trace every active signal in a system.) I'm not a touch typist, never > got that far in school, and my code is often contaminated with such > stuff I have to go back and fix. I've had to use rockhopper, several > times. The output by the time its printed and pasted/taped up, can > occupy a 4x8 sheet of plywood. But it also works. > > Any "spindle-at-speed" signal you generate, should connect only to > motion but I've forgotten the exact name of that pin so dbl-check man > motion to get it right, and nothing else, (except maybe an led in a > pyvcp generated gui) as motion uses the lack of that signal to hold > off the initiation of a synchronized move such as a g76 or g33.1 so > its not started if the spindle just started, generates an index but is > not yet up to speed. > > Because there is an acceleration delay as the axis being moved gets up > to locked speed, if the spindle is not at a constant speed, this delay > will vary causeing an offset in the final locked positions, screwing > up the thread, so LCNC goes out of it way to make sure this signal is > also true. For the same reason you can't start a thread slow, see > that its going to be ok, then grab the rpm slider and crank it up, the > diff in the accell delay will wreck your thread by causeing an offset > between the slow pass and the sped up passes. > > Good luck with the hunting, Dan. And stay well. I just read tonight > there are children that appear to have a different illness from this > covid19, causeing extremely high fevers, heart attacks and strokes. > And here I'm worried because I'm in my 86th trip around this star. > > Cheers, Gene Heskett 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) If we desire respect for the law, we must first make the law respectable. - Louis D. Brandeis Genes Web page <http://geneslinuxbox.net:6309/gene> _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
