Peter Thankyou so much for sharing your trials and discovery. Such knowledge will save a poor beginner like myself much precious sanity.
Regards Cal Grandy Vermont USA Hello Gentlemen, > this is mainly to the EMC developers. > > Since January I have tried to get my steppers run smoothly and evenly. I > wrote several mails to the list on this problem, but received little echo. > Now I seem to be near to the solution which might be of interest to the > developing team. > > My steppers rattled and lost steps regardless of the conditions I gave > them. I've changed almost everything in the setup to get the motors run > correctly. Result: No cure for the problem of "rattling steppers loosing > steps" (name of my former thread). > > - I tried 4 different motherboards from 350 MHz Intel to 2.4 GHz AMD > - I tried 3 newly installed harddisks with two different live CD's > downloaded 2008 and 2009 > - I tried running EMC from the live disks directly > - I tried all this with two different driver boards > - I tested all axis independently and in common > - I made a LED test plug for the printer cable to visualize the timing > with > little sockets to access the signals with a scope probe > - I changed the order of pulse and direction output at the pins of the > parport > - I commented all "reset" lines in .hal to switch off doublestep like I > was > told > - I varied the parameters of steplen and stepspace in .hal up and down to > extreme values > - I had a friend (informatics expert) do all this again to exclude my > person as the source of trouble (which is the most likely cause of > computer > problems) > - I looked at the pulses at the parport with two different oscilloscopes > and found that the pulses came rather irregularly (the old scope couldn't > even trigger it). > > Finally I noticed: only 3 successive pulses (5 us) came with a constant > pause in between, the fourth pause was twice as long which caused the > motors to dance a 5/4 waltz no matter what speed I chose. This could be > influenced only by varying the microstep rate from half to 1/4 or 1/8 > step. > The longer pause seemed to appear then as the eighth or the sixteenth one > correspondingly (hard to get a steady picture for counting them on the > scope). > > To put it shortly: I found no solution and came to the conclusion that > nobody in the world ever tried running steppers with EMC stepconf because > I > never heard anything about it and nobody answered to my mails about it. > All > this troubleshooting took me about two months since I sometimes have to > earn some money, too, and almost all my nerves. > > Note that I did all this with the "test axis" function of stepconf because > this is a very convenient way to see the result of parameter variations > immediately. Now, yesterday evening it occurred to me that stepconf > apparently ignores settings in .hal and .ini files that I made with the > editor when going beyond its apparent default limits. I made a micky mouse > G-Code list and tested this with axis instead of stepconf, ad lo and > behold! the problem was solved! (A little time jitter was still present > but > bearable). > > I resisted my instant urge to dance on the table only because there was no > space on any table. Can you imagine, by the way, what my house looks like > meanwhile? My wife told me that if I wouldn't get all the equipment > mentioned out of the way (I piled it up in 3 rooms), she would, which > could > become a serious case - wars originated from lesser causes.;-)) > > Seriously: After all my efforts I am inclined to exclude all other causes > of the misbehaviour than stepconf. Is it really true that nobody ever > reported problems with the "test axis" function of stepconf? Maybe it has > been fixed in 2.3? I have the impression that it must be a minor bug when > counting the pulses because there is a connection with the microstep > feature. > > I am aware that expositions now have caught all the attention of the gang. > But when NAMES and EMC expo are over, please someone would have a look at > this? > > Thank you for the learning > > Peter Blodow > ------------------------------------------------------------------------------ > _______________________________________________ > 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
