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. >> >> 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. 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. 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
