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  1. #1
    Join Date
    Jan 2009
    Posts
    56

    Help with joint following error on rapids?

    When I run my router I need to slow my rapids to about 100 in/min (depnding on my ferror value) so that i don't get a joint following error. I am puzzled by this since when i am in the Step Conifuration wizard I can run tests for each axis and run around 480 in/min (8 in/sec) with acceleration values of 100 in/sec². When i originally designed my machine I selected my encoders to make sure I wasn't going to exceed the capability of my computer. So here is my questions...why would step configuration wizard allow me to run faster than I can run an actually program? From much of what I have read the step configuration wizard is a good way to test how fast the machine can run. What am I missing?

    Thanks!

  2. #2
    Join Date
    Sep 2006
    Posts
    509
    Not sure about this but maybe you can add a few details about your machine.

    One guess I have is that this might be a machine issue and not necessarily EMC2 related.

    Does the problem only show up on combined moves of 2 or more axis at a time? If so it might be a supply voltage issue to the motors / drives - when running all the drives at once the voltage drops and then it can't keep up?

    Hope this helps - let us know if you figure it out.

    Mike

  3. #3
    Join Date
    Mar 2008
    Posts
    267
    From memmory in the .ini file there are two following error statements per axis.

    One defines folwoinfg error for high speeds the other for low speed and anything else in between is interpolated.

    So go to Your .ini file ( home directory contains emc2 directory whihc contains the ini file) use gedit to open the file and edit it.

    Increase the following error limit for high speed save the file and restart EMC2 .
    Try the condition whihc gave you the error and see if it is recreated.

    Keep increasing until the the error condition just disapears.

    Now go back tot he low speed folwing error setting and reduce it until eror is reprted and then crank back so that the error condition does not occur on low speed ( this would be low G01, G02, G03 and other coordinated moves).

  4. #4
    You can test the maximum and minimum folow error by minmax function

    loadrt minmax count=2

    addf minmax.0 servo-thread
    addf minmax.1 servo-thread

    net axis.0.f-error minmax.0.in
    nat axis.2.f-error minmax.1.in

    in minmax.0.min and minmax.1.max you wiil see the maximum value during the all work.
    Iy can help you to determine the real minimum and maximum follow error for your system.

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