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    Height map has a substantial Z offset error with mesh

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    • Phaedruxundefined
      Phaedrux Moderator
      last edited by

      It doesn't look like there is any weirdness with your homing files.
      Do you also have a bed.g macro?
      What does your slicer start gcode look like? Does it call G32?
      When are you running G29 or loading the heightmap?

      I would suggest redefining your trigger height and re-running mesh compensation with 2.03.

      https://duet3d.dozuki.com/Wiki/Test_and_calibrate_the_Z_probe

      Z-Bot CoreXY Build | Thingiverse Profile

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      • Origamiundefined
        Origami
        last edited by Origami

        This is my starting gcode:

        M572 D0 S0.2 ;Pressure Advance
        M82 ;absolute extrusion mode
        G90; Use logical positioning
        G92 E0 ;Nulls out the extruder
        G28; Homes the nozzle on x,y,z
        G28 Z; Homes the z axis again
        G30; Home z again with probe
        G29 S1; load last bed mesh from memory
        G4 S15; waits 15 seconds for the heaters to recover

        G1 Z5 ;moves up a bit
        G1 X295 Y30 F2700 ;moves over the front right corner.
        G1 Z0.3 F100; height of small blob
        M106 S255 ;turns fan on full
        G1 E20 F200;extrudes a small blob
        G4 P4000; Waits 4 seconds to the blob to cool a bit
        G1 Z0.5 ;moves up a bit
        G4 P5000; Waits 5 seconds to leaker to flow and cool a bit
        G1 Z7 F100; Pull out of the blob a bit
        G4 P5000 ; used for cooling down the stringing
        M106 S0 ;turns fan off
        G92 E0 ;Nulls out the extruder
        M83 ;relative extrusion mode

        I manually do the mesh with the web gui once in a while and the starting gcode just does G29 S1 to load it.

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        • Phaedruxundefined
          Phaedrux Moderator
          last edited by

          That looks ok too.

          As I said above, clear your heightmap, remeasure your trigger height, and then redo the G29 with 2.03. See if the problem persists.

          Z-Bot CoreXY Build | Thingiverse Profile

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          • Origamiundefined
            Origami
            last edited by Origami

            EDIT: also i found the bed.g as well here it is:
            0_1563938574407_bed.g

            I did the Calibrate the Z probe trigger height in the link you provided, also deleted the heightmap file before proceding and im still getting the exact problem.

            alt text
            alt text

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            • Vetiundefined
              Veti
              last edited by

              your bed and hotends have the default B4138 value.
              this is most likely incorrect for your thermistor and will report the wrong temperature.

              Origamiundefined 1 Reply Last reply Reply Quote 0
              • Origamiundefined
                Origami @Veti
                last edited by

                @veti hmm what should I set it to? I have the stock cr10s thermistor for both hotend and bed

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                • Vetiundefined
                  Veti
                  last edited by

                  according to the marlin config
                  https://github.com/MarlinFirmware/Marlin/blob/bugfix-2.0.x/config/examples/Creality/CR-10S/Configuration.h

                  the hotend is a epcos 100k and the bed is a semitec 104GT-2, both can be selected in the duet configurator.

                  Origamiundefined 1 Reply Last reply Reply Quote 0
                  • Origamiundefined
                    Origami @Veti
                    last edited by Origami

                    @veti this may sound stupid but how do i select it in the duet configurator lol... is it the rrf config tool? It just asks me to type in the b value there are no preset selections.

                    alt text

                    I have found the Semitec b value in the wiki here but Epcos 100k have 3 different model so not sure which one I should be using...
                    https://reprap.org/wiki/Thermistor

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                    • Vetiundefined
                      Veti
                      last edited by

                      click into the beta field and the selector will open

                      Origamiundefined 1 Reply Last reply Reply Quote 0
                      • Origamiundefined
                        Origami @Veti
                        last edited by Origami

                        @veti OH now i feel dumb xD thanks for the tip there, got my bed at 4267 and nozzle at 4092 now 😄

                        I looked up datasheet for both thermistor and used that instead of the preset since it seem to be incorrect as the EPCOS was only 10k ohm on the rrf.

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                        • Vetiundefined
                          Veti
                          last edited by

                          you are correct. that is a mistake in the configurator. it is supposed to be 100k and 4092 B
                          see
                          https://github.com/MarlinFirmware/Marlin/blob/bugfix-2.0.x/Marlin/src/module/thermistor/thermistor_1.h

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                          • Origamiundefined
                            Origami
                            last edited by Origami

                            Back on topic tho... I'm running a new bed mesh now with the bed heated up to 60c... I'm sure the temp will be more accurate than before now.

                            but mesh has no luck, bed is still floating in midair on the mesh for some reason..

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                            • Vetiundefined
                              Veti
                              last edited by

                              but it does work if you probe before every print?

                              Origamiundefined 1 Reply Last reply Reply Quote 0
                              • Origamiundefined
                                Origami @Veti
                                last edited by

                                @veti that will have same result, basically my mesh is like 0.7 mm higher than what its supposed to be, I can use the Z baby stepping in web gui to lower the nozzle to around -0.95 mm and it'll print OK. Before the lowest I have used is like -0.25 mm

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                                • Vetiundefined
                                  Veti
                                  last edited by

                                  i am guessing the you are doing the homing with the hotend and bed turned on.
                                  did you create the heighmap under the same conditions?

                                  Origamiundefined 1 Reply Last reply Reply Quote 0
                                  • Origamiundefined
                                    Origami @Veti
                                    last edited by

                                    @veti yes everytime mesh is done it is at printing temp

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                                    • gueee78undefined
                                      gueee78
                                      last edited by

                                      @dc42 do you have any idea what could cause that behavior. I tried to help him find the issue but since z-homing with the mini IR works flawlessly I can't think of what it actually is.
                                      it seems like it just adds a certain offset value to the probe values at some point for no reason.
                                      as if z0 gets redefined after initial z homing.

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                                      • Origamiundefined
                                        Origami
                                        last edited by Origami

                                        Just an update.. I did absolutely no modifications beside the heater stuff yesterday, however today i just did another mesh and there was 1 point that was below 0 and the warning message went away. I started another print and my z babystepping value went from -0.95mm to -0.45mm which is much better than before but still not what I had before which is max -0.25mm.

                                        alt text

                                        JKonopackiundefined 1 Reply Last reply Reply Quote 0
                                        • Vetiundefined
                                          Veti
                                          last edited by

                                          you are probing on glass with an Ir sensor.
                                          check that the point where you are probing does not have any special feature, since its the center and that is where the thermistor is.

                                          do check the repeatrability of your probe at different places.
                                          https://forum.duet3d.com/topic/6962/m48-measure-z-probe-repeatability-and-print-to-serial-output/7

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                                          • gueee78undefined
                                            gueee78
                                            last edited by

                                            Hey Veti,

                                            no he's not probing on glass he uses a TH3D sheet, completely opak and it worked flawlessly before. That phenomenonm started to appear all of a sudden with nothing changed. Btw it got better again, but the repeatability is still rather bad.
                                            Switchin the printer off and on again usually trows the settings off by about 0.3mm wich is way too much imo.

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