Jon Elson wrote: > Andrew Ayre wrote: >> Hi, I've been happily generating g-code files and cutting them with >> AXIS. I'm using EMC2 pre-2.2 CVS HEAD. Yes, I know it's old but I have >> everything working and I am reluctant to change it right now as I am >> trying to get Christmas gifts made as quickly as possible. >> >> With a new g-code file I get "Joint 0 Following Error" at the same point >> every time in the file. Line 161 I believe. The g-code file is here: >> >> http://files.britishideas.com/public/emc2/jointerror1.ngc >> >> On April 17th, 2007 Chris Radek said this about the error message: >> >> "It means the difference between the commanded position and feedback >> position differ by more than the allowed following error." >> >> I am using a simple, HobbyCNC card with steppers, three axis, no >> feedback. I have backlash compensation set in the emc2 ini file. I have >> cut lots of g-code files without a problem until now. Can anyone give me >> some hints on how to solve this? Is it a problem with the g-code? >> > A following error in this case means that the commanded velocity > required more steps/second than the step generator could produce, with > the settings of your system. It may be possible to make the step > generator run faster by decreasing the value of BASE_PERIOD in the > [EMCMOT] section of your .ini file. Warning! If you make this value > too small, your system will freeze up when you start EMC. A quick check > would be to set your feed override to 50% and see if the program gets > past this spot. I didn't see anything near line 161 that looked like a > sudden fast and long move. I do notice some G00 moves at other spots, > which would command the fastest motion permitted by the .ini file > parameters. That would be where I'd expect to see a following error. A > 50% feed override ALSO affects G00 moves, so all motion should slow to > 50%, and it should get past the bad spot. If it is really tripping on a > G00 move, then you need to lower the MAX velocity in your .ini file > (unless speeding up the BASE_PERIOD is possible.)
Thanks for the detailed reply. I set the feed override to 44% and it works (slowly), but I would like to better understand this so I can avoid this in the future. I've set the BASE_PERIOD based on the latency test, and it is the maximum my machine can run at. It gives me a max speed of 71.6 IPM. I can't decrease this value, unfortunately. The g-code file is supposed to limit the speed to 30 IPM, and you can see this when running the file in AXIS. However I now notice that when the file is running in AXIS the velocity occasionally and only for a split second displays a value of 71.6 IPM. This raises two questions for me: - why would a movement cause the velocity to go beyond the maximum of 30 IPM that I set? Is that a problem with AXIS/EMC2 or the g-code? - is this a symptom of the problem or is it normal? thanks, Andy -- Andy PGP Key ID: 0xDC1B5864 ------------------------------------------------------------------------- This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
