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    Z-offset is very high

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    • hevilp
      hevilp last edited by hevilp

      Hi,

      I got a the v1.2 from precision piezo uk as endstop.

      I use:
      M558 P8 I1 R0.4 F300 Z1

      My homez.g:

      G91 ; relative mode
      G1 Z4 F400 ; lowers bed 4mm to avoid dragging nozzle over the bed
      G90 ; back to absolute mode
      G1 X200 Y180 F4000 ; Move probe to middle of bed
      G30 ; probe
      G91 ; relative mode
      G1 Z4 F150 ; move slowly 4mm in the +Z direction
      G90 ; back to absolute mode
      G30 ; probe
      G1 Z2.5 F150 ;Move Z to 2.5 above the bed
      ;G31 X0 Y0 Z-0.15
      G90 ;back to absolute
      ; G1 X0 F4000 ;move to X0

      The probe is very nice and I use a high sensetive.

      When do "G1 Z0" the nozzle goes a little bit into the bed.
      When I do G30 the carriage is not moved when the nozzle touches the bed.

      Why G30 and G1 Z0 differs so much?
      If I want to correct that, I need a very high negative offset or?

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      • Phaedrux
        Phaedrux Moderator last edited by Phaedrux

        G30 uses the values from M558 and will tell the system where z0 is, G1 will not.

        Have you calibrated the zprobe trigger offset? https://duet3d.dozuki.com/Wiki/Test_and_calibrate_the_Z_probe#Section_Calibrate_the_Z_probe_trigger_height

        What does the G31 command look like in your config.g?

        Z-Bot CoreXY Build | Thingiverse Profile

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        • hevilp
          hevilp last edited by

          With G30 I do my Z-Probe right?

          M558 P8 I1 R0.4 F300 Z1
          means: If the piezo gets triggered, there is Z0, right?

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          • Phaedrux
            Phaedrux Moderator last edited by

            That is correct, but you first need to tell the system where the nozzle is in relation to the bed when the probe triggers using G31 Zn. In the case of the piezo probe Zn is a slightly negative value normally, but you can't be sure until you do a trigger height calibration as described in the link I posted.

            Z-Bot CoreXY Build | Thingiverse Profile

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            • hevilp
              hevilp last edited by

              I did all in your link, it comes -0.14. and I got it in my homez.g "G31 X0 Y0 Z-0.14", not in my config.g. (Like before).Of course I always do a G28 so it is set always.

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              • hevilp
                hevilp last edited by hevilp

                Do I need G92 with piezo? In normal case, everytime when the piezo is triggered, something between 0,05 and 0,15mm over the triggerpoint is Z0 or? Maybe my error is depending on my other thread, that G31 is always 0. The offset is ignored I think

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                • Phaedrux
                  Phaedrux Moderator last edited by

                  @hevilp said in Z-offset is very high:

                  G31 X0 Y0 Z-0.14

                  This should be in your config.g

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                  • hevilp
                    hevilp last edited by

                    @phaedrux said in Z-offset is very high:

                    G31 X0 Y0 Z-0.14

                    Okay, I will move it, if I set it manually, even for X or Y, it always reports 0. I just updated to the latest firmware, and there is it always 0, too.

                    Phaedrux 1 Reply Last reply Reply Quote 0
                    • Phaedrux
                      Phaedrux Moderator @hevilp last edited by

                      @hevilp See your other thread for why it reports 0.

                      If you send G31 T8 it will report the current settings.

                      Z-Bot CoreXY Build | Thingiverse Profile

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