Z probe question



  • With a Z axis calibration I sometimes see the number 1000 in red in the status box at sensors / Z-probe when it triggers, but most of the time it stays at 0 (not in red) when triggering.
    What does that mean?

    Calibration looks ok though,
    " G32 Calibrated 6 factors using 13 points, (mean, deviation) before (0.996, 0.048) after (-0.000, 0.046) "

    To give the probe some more room I changed M558 H30 to H35 in the config.g, but that hasn't changed anything, besides that the calibration is going damn slow now 🤔

    Printer: Anycubic Predator
    Controller: Duet 2 wifi / PanelDue (firmware 3.1.1)
    Probe: standart Anycubic Predator one with a micro switch.

    Schermafbeelding 2020-10-22 om 18.38.10.png



  • that means its triggered.



  • Ok, but what is the reason that I don't see the number 1000 in red with every trigger?



  • @holco62

    the webpage only updates in intervals. if the trigger happends between the interval, you will not see a change in the value.


  • Moderator

    If you click the switch with your finger and hold it down, it may show as 1000 for longer.

    The important thing is that triggering the switch stops a probing move (G30). If it does that, it's working fine.

    I do wish the probe display on the web interface would take the raw values the firmware gets and translated it into a more useful piece of info, like last triggered 10 seconds ago with value 1000. But that's more info than can fit into a small box.



  • Okay, that explains a lot 👍

    One thing though, why is the calibration so damn slow now after I changed M558 H30 to H35 in the config.g?



  • Is it possible to make the calibrations faster anyway?


  • Moderator

    What is your entire M558 command?

    H30 versus H35 adds an extra 5mm of travel, so that will take longer. You can increase the dive speed perhaps or reduce the dive height, that's your two options for reducing the time taken.



  • ; Z-Probe
    M558 P8 C"zprobe.in" R0.4 H35
    F1200 T5000 ; set Z probe type to unmodulated and the dive height + speeds
    G31 P500 X0 Y0 Z13.90 ; set Z probe trigger value, offset and trigger height
    M557 R175 S20 ; define mesh grid



  • The calibration now does 2 mm / s 😴



  • @holco62
    its always a good idea to read the documentation as to what the parameters do.

    https://duet3d.dozuki.com/Wiki/Gcode#Section_M558_Set_Z_probe_type

    You are probably looking for the F parameter


  • Moderator

    Keep in mind that M558 F will still be limited by your max Z speed set by M203.

    Since your trigger height is nearly 14mm using 35mm dive height is probably overkill. You really only need to lift high enough to ensure the probe is clear of the bed before probing again. M558 H20 should be enough.



  • Thanks for the feedbacks, I'm a bit wiser again 🙂


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