BL Touch selftest gcode causes probe to cycle nonstop



  • Hi,

    ive been spending hours trying to get a bl touch working but i have the problem that the

    M280 P3 S120 I1

    selftest command causes the BL touch to nonstop cycle in and out instead of only one or two times as supposed to.

    i switched the Bl touch with a different probe and get the same problem.

    all the other commands work, deploy, retract, and even the probe input responds when i trigger the probe manually.

    does someone have an idea what else i can try? i somehow suspect that the issue is with the Duet, i coudnt find anyone having a simmiliar issue (non stop cycling) with a bl touch.

    thanks in advance!



  • The selftest command is supposed to do an endless cycle, mine does that too.
    The "startup selftest" when the BLTouch gets powered (printer switched on) is two times only, but there is no command for the "startup selftest".

    When the probe input responds when you trigger the probe manually, it sounds like it is working ?
    Have you tried to move your probe up above the bed a bit and issue a "G30 S-1" (you may have to home x and y first) and trigger the probe manually with a light touch against the pin ? This should stop the movement and show you that everything works as it should. Keep a finger near the power button of you printer so you can stop it if the touch against the pin isn't stopping the movement.



  • Mine will continuously cycle also. Nothing out of the ordinary.


  • administrators

    @vhoward @Scachi

    I have added line to the guide, see this post
    https://forum.duet3d.com/post/50206


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