John Kasunich wrote: > Andy Holcomb wrote: >> John Kasunich wrote: >>> Andy Holcomb wrote: >>>> On EMC1, I was running Axis speeds of more than 120ipm, I can't get EMC >>>> 2 past around 60. I am running a 1.6 ghz computer. > >>> Steppers or servos? >> Steppers >>> What step frequency does your machine need to get 120ipm? > > You didn't answer this one. 4000 steps per inch (120 * 4000)/60 = 8000 ? > >>> What is your BASE_PERIOD? (It needs to be high enough to generate the >>> needed step frequency.) >> On Emc 1 you lowered the base_period, you have stated "high enough", has >> EMC2 changed this? My base_period is currently at 11000 I can't go any lower > > Sorry, I was thinking in terms of frequency, not period. > > 11000 is pretty fast. Assuming you don't have any special timing > requirements, that means you can generate one step every 22uS, or > 45,000 steps per second. Since you didn't say how many steps you > need to reach the desired speed, I don't know if the problem is: > > A) you need 60,000 steps/sec (ain't gonna happen), or > B) you need 30,000 steps/sec, and we need to figure out why you aren't > getting that many. > > I'm going to assume B - EMC2 is unlikely to be significantly slower then > EMC1 when properly configured. > >>> Have you seen any error messages, or does it just not go fast enough? >> Yes, example "Joint 0 following error" > > Following errors should never happen on a properly configured stepper > system. > > I don't know what version you are running - 2.1.4 is the latest, but any > 2.1.x should be fine for this particular issue. If you have something > older please say so. Latest Live version > > Pre-2.1 versions would give following errors if EMC is configured for a > speed that the computer can't deliver. 2.1.0 and later should print an > error message at startup if you ask for more than the computer can give. > > Do you have adequate stepgen headroom? The following snippet is from > the sample config "stepper_inch.ini": > > > MAX_VELOCITY = 1.2 > > # NOTE: the step generator module applies its own limits to > > # acceleration and velocity. We have discovered that it needs > > # to have a little "headroom" over the accel by the trajectory > > # planner, otherwise it can fall slightly behind during accel > > # and later overshoot as it catches up. In the long term we > > # hope to come up with a clean fix for this problem. In the > > # meantime, please set STEPGEN_MAXACCEL below to a few percent > > # higher than the regular acceleration limit MAX_ACCELERATION > > MAX_ACCELERATION = 20.0 > > STEPGEN_MAXVEL = 1.4 > > STEPGEN_MAXACCEL = 21.0 > > MAX_VELOCITY of 1.2 inches per second means 72 ipm. For 120 ipm, > you need to set MAX_VELOCITY to 2.0, and you need to set STEPGEN_MAXVEL > to something higher than 2.0, perhaps 2.2. If you don't do that you > will get following errors. > what is adaquate? I have allowed headroom on accel I will mess with it on velocity > Regards, > > John Kasunich > > > ------------------------------------------------------------------------- > Take Surveys. Earn Cash. Influence the Future of IT > Join SourceForge.net's Techsay panel and you'll get the chance to share your > opinions on IT & business topics through brief surveys-and earn cash > http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users >
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