andyholcomb wrote: > > John Kasunich wrote: >> Stephen Wille Padnos wrote: >> There's not much more we can do without knowing what we're chasing. >> >> >> Seconded - although you've provided some description of the symptoms, it >> is really rather vague and raises more questions than it answers. We're >> discussing it on IRC at the moment, and it seems like every other >> statement is something like "I think he means....(something)". >> >> For example, in your first message you mentioned something about 20-30 >> degrees of movement. I assume that is movement of your leadscrew or >> maybe motor shaft? In any case, 20-30 degrees is a lot of steps - even >> for a full-step drive that is something like 20 steps, for a >> microstepped drive it could be 100 or more. But the "4th 5th 6th" >> decimal place jittering you are describing sounds like only one or two >> steps at the most. So which is it? Jittering typically means moving >> back and forth with no net movement, but again, 20-30 degrees is a lot >> of movement. >> > Sorry does 2 things, one is the 10 to 20 degrees on the stepper > shaft/screw (1to1), the second is a real slow vibration/jitter that move > the stepper at a rate of about 90degs per 30 seconds. I have not seen it > do the 1st for a little while, all I have seen it do lately is the > second method.
OK, we have a communication problem here. The term jitter usually means some small motion back and forth around a fixed location. If your motor is turning 90 degrees (no matter how slowly), that is creep. You might have jitter too - if it goes three steps forward then two steps back and makes slow steady progress in one direction, then you have jitter _and_ creep. In any case, the creep problem is almost certainly between stepgen and your motor. You say EMC's position is only changing in the 4th decimal place - that is NOT a 90 degree movement. One possibility is that EMC is jittering back and forth by one or two steps, but your drivers are missing some of the direction changes, so that when EMC takes two steps forward and two steps back, your drive takes three forward and only one back. You haven't mentioned the drives you are using - are you sure you have dir-setup and dir-hold set properly for those drives? >> Is there any way you can get in IRC from the EMC computer so we can ask >> questions in more detail and get immediate answers (that would also let >> you run tests and immediately report the results). >> > I don't have a problem getting on IRC, I would rather talk though, I > type too slow. Write me off the list and I can get you a number or you > can give me yours if you want. > > PS, in my message with the Stephen I have figured out that it does not > do it if I put my backlashes back to 0. I have my scale set to 40000 also. > There are several people who might have something to contribute to this problem, and a phone call only connects one person to you. Regards, John Kasunich ------------------------------------------------------------------------- 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
