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Electronics help - Servo drive issues on mill

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  • #16
    I think I have fixed it

    Two parameters -

    PN020 - Motor rated speed - this is set by default motor settings
    PN051 - Motor Max Speed - this is a user adjustable one

    PN051 Max was set at 3000 - i had tweaked this before but not the other one as it's a default setup one.

    I have now set both to 3050rpm and away she goes

    My working theory is that the controller was calling for 3000 but the drive was maxing out somewhere around 2990 - (where it faulted) so it was stuck in an endless fault loop - controller saying "I want more” and the drive saying “you can't have it”

    Short video…

    I think it makes sense??

    Also in the video you can see it runs with a error of about 1980 - is that god, bad, ugly??

    I can tune it but have not idea of tuning spindles - as said above, they are nothing like axes drives.
    If it does'nt fit, hit it.


    • #17
      Still has me wondering what the units of measurement are for that following error count. Being over 2000 I have to conclude it cannot be rpm's. I now am thinking its encoder counts. For example, if it was a 2000 line encoder and the following error was 2000 then its only out of "sync" by one revolution which is very close.

      Have you tried putting a small value into I of the PID section? I would think that would be required for good close in regulation when close to the target commanded speed. Experimenting with adding I may cut your following error down even more. Values of I will be very small, 5% or less of what P is.

      Setting the max speed at slightly over the required speed is standard procedure. You don't want the 10V line maxed out and still be a few rpm short of the target.

      Its tough with no good documentation.
      Last edited by Sparky_NY; 05-28-2019, 08:03 AM.


      • #18
        As far as i know, it is encoder pulses - these are 10,000 pulse encoders (2500PPR * 4 edges) so its less than 1/4 of a turn off.

        I will continue to tweak now i know it is running ok

        Thanks for the advice.
        If it does'nt fit, hit it.