On Thursday 21 August 2014 10:56:33 Ricardo Moscoloni did opine And Gene did reply: > Couldnt agree more with Ben Potter comment about inverting stepgen > signals . I pull my hair out trying to debug this, hundreds of test > later i came to the same conclusion. The problem was on one axis only > in mine too.. > regards > rick
Just to clarify this in my own wet ram, I am used to seeing, for a slow speed command, a narrow positive pulse at my BOB's output on an external oscilloscope. However, with the 2m542 drivers, I could use either polarity as the BOB can drive both ways, and the 2m542 input is independent & therefore reversible, so the drive would not be aware of the difference. I don't know anything about the G540's, do they bring out both ends of the opto? If they do, the same trick should work for them. I suspect, from the conversations I've copied here, that the gecko drives only accept a direction change in the "between" steps state. And if the step polarity is wrong, the dirhold and dirsetup constraints are probably being violated. If micro-stepping, its not going to be very much per direction reversal and would take a while for the error to be noticeable. But there it is. One way to possibly check this is to setup a dial on the axis, and let the stepgen configuration run it back and forth 20 thou at a speed that won't kill the indicator gears and see if the dial stops at the same place over an extended period of time. > 2014-08-10 18:51 GMT-03:00 Ben Potter <b...@bpuk.org>: > > Very late to this discussion. I had this problem about a month back, > > with an incredible amount of frustration. > > > > In the end I found that on my G540 I had to invert the stepgen > > output. When inverted, no problems, when noninverted - one axis only > > would slowly slip regardless of step timings. > > > > I'm stuffed if I know _why_ inverting the step output would affect > > the drives behaviour to this degree - but if all else fails... > > > > > > -----Original Message----- > > From: John Alexander Stewart [mailto:ivatt...@gmail.com] > > Sent: 10 August 2014 22:21 > > To: Enhanced Machine Controller (EMC) > > Subject: Re: [Emc-users] G540, 5i25, missing steps, once again. > > > > Yes! Success! > > > > setp hm2_5i25.0.stepgen.00.position-scale [AXIS_0]SCALE setp > > hm2_5i25.0.stepgen.00.steplen 2500 setp > > hm2_5i25.0.stepgen.00.stepspace 2500 setp > > hm2_5i25.0.stepgen.00.dirhold 2500 setp > > hm2_5i25.0.stepgen.00.dirsetup 2500 > > > > worked, no axis slip over a 4 hour test. > > > > I think I'll set everything up with even more time, and call it a day > > (or, 4 weekend days, to tell you how long I've been looking at this) > > > > Thanks all! > > --------------------------------------------------------------------- > > ------- -- > > _______________________________________________ > > Emc-users mailing list > > Emc-users@lists.sourceforge.net > > https://lists.sourceforge.net/lists/listinfo/emc-users > > > > > > --------------------------------------------------------------------- > > --------- _______________________________________________ > > Emc-users mailing list > > Emc-users@lists.sourceforge.net > > https://lists.sourceforge.net/lists/listinfo/emc-users > > ----------------------------------------------------------------------- > ------- Slashdot TV. > Video for Nerds. Stuff that matters. > http://tv.slashdot.org/ > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users 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> US V Castleman, SCOTUS, Mar 2014 is grounds for Impeaching SCOTUS ------------------------------------------------------------------------------ Slashdot TV. Video for Nerds. Stuff that matters. http://tv.slashdot.org/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
