On Monday 05 November 2018 06:31:51 theman whosoldtheworld wrote: > seems a backslash mechanical problem .... or to low power on stepper > drive for low motion (if you have these option) or a acc / dec ramp > too low... so the stepper stop before to go at real measure. > > regards > bkt > I hadn't considered the ACCEL settings in the ini as being a cause, but raising the stepgen ACCEL and the scaled up anywhere to 100% MAX_ACCEL in the ini section for that axis might be an educational test. Of course if the motor stalls with a minor increase, then the first setting for ACCEL should be lowered a bit, the point being that you stay within the motors working envelope. In two of my machines, there is a diff in motor supply voltage, 28 in one, and 37 to 38 in the other, and the higher voltage more then doubles the motor speed attainable.
There is also the possibility that the OP has a DEADBAND setting, which is not normally used with steppers but left out or set to zero. > Il giorno lun 5 nov 2018 alle ore 00:19 John Dammeyer < > > jo...@autoartisans.com> ha scritto: > > This discussion of servo gear heads brings up an interesting > > question for me. > > > > I've been working on a system that has a CANopen controller > > Step/Servo with integrated encoder. The motor turns a lead screw > > (10 TPI) which moves a scissor jack type mechanism. We have an > > extra external encoder mounted on the screw to be able to determine > > where the screw is on power up since it could be anywhere. The > > step/servo is configured to have 200 steps per rev which still works > > out to 0.0005" of linear movement. More than accurate enough. > > > > What we're finding is that occasionally, a CAN message with a Move > > to Position command of 2549 steps moves one or two less steps than > > it should. To position 2547. The status CANopen message does not > > report move complete. > > Our software times out waiting for that move complete message after > > 15 seconds. The actual move up to that position is only 4 seconds. > > So the step/servo has over 10 seconds to move 1.8 to 3.6 degrees (2 > > steps) to reach > > the end of move position. > > > > I've been told to ignore this and when the external encoder is close > > enough go on with the rest of the motion profile. In other words, > > ignore that the motor isn't reaching the target position. > > > > If I allowed my Electronic Lead Screw to not always reach the end > > position I > > think I'd have users > > complaining. > > > > The process isn't severely compromised by that two step shortfall. > > So we can go on by ignoring motion complete. But this has all the > > appearance of something that will fail worse later on if not > > addressed. > > > > Am I being too fussy? > > > > Thanks > > John > > > > > > > > > > _______________________________________________ > > 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 -- Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Genes Web page <http://geneslinuxbox.net:6309/gene> _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
