U-axis without limit

  • Hi
    I have defined a u-axis (M584 X0 Y1 Z2 U4 E3) which works perfect. The problem now is, that I need "infinite" rotation on this axis. This means I don't want to have an upper limit. Even I define only limits with M208 for x, y and z, the u-axis still stops at 250. I also don't want to disable the limits with M564.
    Is there any possibility to use an axis without a limit and have a limit for the other axis?

    Thank you.

  • I have no idea how stupid my idea is, but you can try. As limiting command M208 must be after M584 command to work, you should try this:
    M584 X0 Y1 Z2 E3
    M208 (your limits)S0
    M208 (your limits)S1
    M584 U4

    And as i said, have no clue if its really works that way, so sorry wasting your time if it does not.

  • Have you tried giving it a maximum and minimum of 0?

  • Thank you for your ideas. I have testet them both. Unfortunately both do not work. With both I can only move from 0 - 200 then it stops. I assume, that 200 is the default limit.
    Any other ideas?

  • What for you using it? If you could define it as extruder, then you dont have limits. Only limit for extruder is temperature but you can always allow cold extrusion.

  • I did already try it as an extruder axis. But there are two big disadvantage:

    • there is no possibility for a homing on an extrusion axis (as far as I know). And we need homing to know in which position the axis is.
    • only relative movement is allowed, which is not the best for the application.

  • you could put a very high value in, such as 1000000. How infinite do you need it to be?

  • Yes, if there is no other solution, this may be what I will do. And maybe I can reset the position with G92 if it gets too high. But no limit would still be better...

  • one for @dc42 to point in the right direction

  • Moderator

    Moved to the firmware wishlist area for @dc42 to see.

  • administrators

    I've added this to the work list for RRF 3.2. RRF already supports continuous rotation axes for certain kinematics, but at present there is no way to configure an axes as a continuous rotation axis manually.

  • Thank you for your answer. What kinematics do have continuous rotation axis? How can I choose it? Maybe I can make a work around, since the gcode is not generated by a slicer, but by a script code, which I made myself.

  • administrators

    Continuous rotation axes can be created in the latest firmware builds from the v3.02-dev branch on github.

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