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    Dual motor bed tilt-compensation only goes through the motions

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    • Vetiundefined
      Veti
      last edited by Veti

      @equanimity8 said in Dual motor bed tilt-compensation only goes through the motions:

      M671 X105:105 Y0:150 S5 ; leadscrews at left (connected to Z) and right (connected to E1) of X axis
      M208 X0 Y0 Z0 S1 ; set axis minima
      M208 X210 Y150 Z150 S0 ; set axis maxima

      this would mean that the leadscrews are inside the bed. that seems incorrect

      G31 X0 Y0 Z-0.25 P600

      what kind of probe is it?

      M305 P1 T100000 B4138 R4700 ; set thermistor + ADC parameters for heater 1

      your thermistor config is wrong. look up the correct beta value in your thermistor documentation.

      also check that you are on at least firmware 2.05.1

      gloomyandyundefined 1 Reply Last reply Reply Quote 0
      • equanimity8undefined
        equanimity8
        last edited by

        @Veti I have redacted my config.g to M671 X105:105 Y-20:170 S5 and it made no difference.

        The probe is a precision piezo.

        What makes you think my thermistor value is wrong? I printed a successful calibration cube and all readings seemed accurate. This is a freshly configured firmware, should it make a difference, but my previous setup was identical in that regard.

        I am indeed running 2.05.1.

        Vetiundefined 1 Reply Last reply Reply Quote 0
        • gloomyandyundefined
          gloomyandy @Veti
          last edited by

          @Veti said in Dual motor bed tilt-compensation only goes through the motions:

          this would mean that the leadscrews are inside the bed. that seems incorrect

          I think this depends on how the bed is supported. My understanding is that what you need to specify is the locations at which the bed pivots. In the case of a conventional prusa style bed with two lead screws either side of a bed with a subframe this will be at the leadscrew positions. But with a corexy you often have a rigid plate style bed that pivots at the support points, in which case you want to use the positions of the support points. At least I think that is how it works!

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          • Vetiundefined
            Veti @equanimity8
            last edited by

            @equanimity8 said in Dual motor bed tilt-compensation only goes through the motions:

            What makes you think my thermistor value is wrong? I printed a successful calibration cube and all readings seemed accurate.

            because 4138 is the default, and for a thermistor that has not been in use for some time.
            the dimension have nothing to do with this.

            depending on your thermistor, the actual temperature can easily be off by 20 degrees.

            M584 X0 Y1 Z2:4 E3

            is your second z really connected on the e1 and not the second z?

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            • equanimity8undefined
              equanimity8
              last edited by

              @Veti
              Thanks for clarifying. I looked up E3D's v6 documentation and they indeed specify a different value (M305 P1 B4725 C7.060000e-8).

              Yes, my second motor is connected to driver e1, no independent motor tilt-compensation would be possible otherwise.

              Vetiundefined 1 Reply Last reply Reply Quote 0
              • Vetiundefined
                Veti @equanimity8
                last edited by

                @equanimity8
                M561 ; clear any bed transform
                G28 ; home

                your home load the height map again.

                remove the G29 S1 from the homeall and move that to the start of your slicer

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                • equanimity8undefined
                  equanimity8
                  last edited by

                  @Veti
                  I commented out G29 S1 and there was no change in behaviour i.e. my bed compensation mesh still shows significant tilt that should have been corrected by G32.

                  Further, why would G28 load my height map again? To the best of my knowledge, it homes all axes, it doesn't execute homeall.g.

                  Vetiundefined 1 Reply Last reply Reply Quote 0
                  • Vetiundefined
                    Veti @equanimity8
                    last edited by Veti

                    @equanimity8 said in Dual motor bed tilt-compensation only goes through the motions:

                    Further, why would G28 load my height map again? To the best of my knowledge, it homes all axes, it doesn't execute homeall.g.

                    that is not true. and you can easily test this by executing G28 twice from the console.

                    can you run 3 G32 in succession and post the output?

                    btw where is your M557 definition for the mesh?

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                    • equanimity8undefined
                      equanimity8
                      last edited by

                      The console output of 3 consequitive G32s:

                      11/1/2020, 12:09:59 PM	G32
                      Leadscrew adjustments made: 0.019 -0.044, points used 2, deviation before 0.028 after 0.000
                      11/1/2020, 12:09:43 PM	G32
                      Leadscrew adjustments made: 0.007 -0.057, points used 2, deviation before 0.035 after 0.000
                      11/1/2020, 12:09:32 PM	G32
                      Leadscrew adjustments made: 0.019 -0.044, points used 2, deviation before 0.028 after 0.000
                      

                      I execute it from a macro, which is as follows:

                      M557 X0:210 Y0:150 S30
                      G29
                      
                      Vetiundefined 1 Reply Last reply Reply Quote 0
                      • Vetiundefined
                        Veti @equanimity8
                        last edited by

                        @equanimity8 said in Dual motor bed tilt-compensation only goes through the motions:

                        The console output of 3 consequitive G32s:

                        the output suggest its already level as those error are normally within the probes inaccuracies

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                        • equanimity8undefined
                          equanimity8
                          last edited by equanimity8

                          This is a screenshot of my height map and the relevant statistics after G32 and mesh bed compensation. Should I assume that this is normal, given the capabilities of my setup and that there is no way to improve it without improving the hardware?
                          1.PNG

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                          • Vetiundefined
                            Veti
                            last edited by Veti

                            @Veti said in Dual motor bed tilt-compensation only goes through the motions:

                            M671 X105:105 Y0:150 S5 ;

                            your leadscrews are at the middle top and bottom. it can only change an error in the y plane

                            adjustments to the leadscrews can not possibly change a twist in the opposite x plane.
                            you need 3 leadscrews for that

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                            • equanimity8undefined
                              equanimity8
                              last edited by

                              Yep, I though the same but I wanted to make sure after, apparently I got the initial misconception about G28. Thanks a lot for clarifying that to me! Enjoy your weekend!

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