On Friday 31 March 2017 11:32:53 Kenneth Lerman wrote: > Up the thread a ways, Gene commented that the MPG generates one count > per detent. > > I thought that the encoder in the MPG generates one *cycle* per > detent. A cycle is represents four quadrature edges which means that > you get four counts per cycle. So that's four counts per detent. > > There is a complication that there is one count of hysteresis involved > here. So if you turn clockwise and then reverse directions, you might > be off one count from where you started. If you repeatedly go back and > forth though, you should not accumulate more than one count of > deadband. > > Going back to Stuart's original post where he says that he sees > motions of .0075 or .01 per click, that is what I would expect if > there was some back and forth motion at some of the clicks. Stuart > also sees that the error is not accumulating. > > My conclusion is that what Stuart is seeing is an artifact, not an > error. > > Ken > I am seeing none of that effect, Kenneth. I bought 3 of those dials, putting 2 of them on the Sheldons apron, but and have checked all three, and all three are A=B=0 at rest. I have not been able to trigger such a 1 count anomaly. Nor have I observed a move (as recorded by the screen DRO) that was not an exact multiple of stepsize-per-click*steps moved.
I would like to have it so the displayed step size was displayed in the metric or imperial measurement system in use by the display, but I have not found a way to extract the view displays mode, either in axis or motion, I find no such pin/signal/parameter available. I wouldn't mind being able to make the size of the jog change according to the view mm/inch mode, making this code much more universally usable regardless of the flag flying over the local real estate. Is there a debug= setting that would cause this to be exposed? Am I blind? > Kenneth Lerman > 55 Main Street > Newtown, CT 06470 > > On Thu, Mar 30, 2017 at 12:54 PM, Jon Elson <el...@pico-systems.com> wrote: > > On 03/30/2017 04:04 AM, andy pugh wrote: > > > On 30 March 2017 at 04:11, Jon Elson <el...@pico-systems.com> wrote: > > >> Now, I am using ilowpass on a 2.6 install, possibly > > >> something has changed. > > > > > > Nothing has changed since 2014 > > > https://github.com/LinuxCNC/linuxcnc/commits/master/src/ > > > > hal/components/ilowpass.comp > > > > > The whole component is only 2 lines of code: > > > > > > ;; > > > value += (in - value) * gain; > > > out = (int)(rtapi_s64)(value * scale); > > > > Right. Jeff Epler wrote that for me at one of the CNC > > Workshops at Roland Freistad's place. It is so SIMPLE, I am > > having some trouble seeing how it could be the culprit, > > unless maybe given very wrong parameters. > > > > Anyway, comparing the input and output from ilowpass should > > confirm that it is (or is not) causing the problem. > > I'm thinking there is a combination of a weak encoder output > > drive, electrical noise, maybe A<-> B crosstalk and the PPMC > > encoder counter is counting somewhat erratically. I think > > putting Halmeter on the encoder count output and then > > cranking the encoder known distances at varying speeds might > > quickly show this is happening. (or not...) > > > > Jon > > > > ------------------------------------------------------------ > > ------------------ > > Check out the vibrant tech community on one of the world's most > > engaging tech sites, Slashdot.org! http://sdm.link/slashdot > > _______________________________________________ > > Emc-developers mailing list > > Emc-developers@lists.sourceforge.net > > https://lists.sourceforge.net/lists/listinfo/emc-developers > > ---------------------------------------------------------------------- >-------- Check out the vibrant tech community on one of the world's > most engaging tech sites, Slashdot.org! http://sdm.link/slashdot > _______________________________________________ > Emc-developers mailing list > Emc-developers@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-developers 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-developers mailing list Emc-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-developers
