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  1. #1
    Hi Nick,

    Here's those way covers I was talking about, pictures didn't do it justice so a little video shows it better. Hope it helps


  2. #2
    Nick's Avatar
    Lives in East Yorkshire, United Kingdom. Last Activity: 06-01-2021 Has been a member for 8-9 years. Has a total post count of 26. Received thanks 2 times, giving thanks to others 0 times.
    Quote Originally Posted by JAZZCNC View Post
    Hi Nick,

    Here's those way covers I was talking about, pictures didn't do it justice so a little video shows it better. Hope it helps

    Ah thank you very much, I see what you mean now, those look great, really simple design, just sheet metal and a few welds. I will give making some a go.

    Following error wise. What speed are you aiming for? How have you found tuning the internal PI loops? I'm struggling to tune the servos. I'm just about at less than 10 microns f-error now on the X and Y, I am cheating slightly acceleration dropped a bit, speed reduced to 1500mm/m. I think my main issue is the servo speed and torque loops aren't tuned. The error got a lot better when I put in the inertia load into Pn257 after I ran the Fn018 mode to get the inertia ratio. I'm using gain adjustment mode 1 (Pn258) and then adjusting the "rigid grade selection" until I get oscillations / vibration. I found the linuxCNC tune very sensitive to FF1

    I haven't worked out how to properly tune the internal PI's because I can't work out how to bring linuxCNC into open loop and then command a specific speed in LinuxCNC. I am thinking about using the internal speed command function and toggling this with push buttons. Say set it to 250, -250rpm and then I will be able to jog it back and fourth while looking at the HAL scope.

    Click image for larger version. 

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  3. #3
    I haven't worked out how to properly tune the internal PI's because I can't work out how to bring linuxCNC into open loop and then command a specific speed in LinuxCNC. I am thinking about using the internal speed command function and toggling this with push buttons. Say set it to 250, -250rpm and then I will be able to jog it back and fourth while looking at the HAL scope.
    Nick. What mode are you using ie position or torque etc. Have you seen or read this:-

    https://forum.linuxcnc.org/10-advanc...etailed-how-to

    I am in the same boat as you and struggling with a following error when using closed loop. Changing closed to open loop is just one change in the hal file.
    This is also my first time with halscope
    ..Clive
    The more you know, The better you know, How little you know

  4. #4
    Nick's Avatar
    Lives in East Yorkshire, United Kingdom. Last Activity: 06-01-2021 Has been a member for 8-9 years. Has a total post count of 26. Received thanks 2 times, giving thanks to others 0 times.
    Quote Originally Posted by Clive S View Post
    Nick. What mode are you using ie position or torque etc. Have you seen or read this:-

    https://forum.linuxcnc.org/10-advanc...etailed-how-to

    I am in the same boat as you and struggling with a following error when using closed loop. Changing closed to open loop is just one change in the hal file.
    This is also my first time with halscope
    Yeah, that's what i've been following, really useful. I also found the John Thornton guide's. Using speed mode, via a mesa 7i77, so linuxCNC is running the position loop.

    I will try torque at some point I think. I'm sure the issue is with the drive speed and torque PI loops. How have you gotten on with setting the drive PI settings? I'f i put it in open loop I think the axis will drift and I don't think I could command an analog signal? or maybe I could?

  5. #5
    Nick, Clive is using Step & Dir Mesa card not Analog +/-10v using Position mode in the drive. He's using the same AASD Drive as you but 30A with 1.8Kw servo.

  6. #6
    Quote Originally Posted by Nick View Post
    Yeah, that's what i've been following, really useful. I also found the John Thornton guide's. Using speed mode, via a mesa 7i77, so linuxCNC is running the position loop.

    I will try torque at some point I think. I'm sure the issue is with the drive speed and torque PI loops. How have you gotten on with setting the drive PI settings? I'f i put it in open loop I think the axis will drift and I don't think I could command an analog signal? or maybe I could?
    I believe that torque mode is more difficult . I am using step/dir not analogue which should be easier.

    I will be away for a few days but will catch up on my return.
    ..Clive
    The more you know, The better you know, How little you know

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