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    No Z idle torque before Z move commands have been send

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    • Nemesisundefined
      Nemesis
      last edited by Nemesis

      I've designed a Cartesian printer (which works brilliantly with the duetwifi 🙂 )

      The Z moves the bed using a two motor setup connected using the Z series outputs on the duet. Because of that the motors may not move independently.

      The problem I currently have is that when I power on the printer it does not apply the Idle torq. As soon as you touch the bed a bit one motor moves down. Which means I have to home the Z turn off the printer make it level and startup the printer again.

      After the first Z move has been performed Idle troque is applied and I'm unable to move the rods by hand (without using excessive force).

      M906 X1200 Y1200 Z1500 E1500:1500:1500:1500 I50
      Motors used:

      Length: 48 mm axis diameter: 5 mm
      Voltage: 3,1 V step angle: 0,9 °
      Holding Torque: 4.0 kg-cm Weight: 360 g
      Aantal draden: 4 Type: 42BYGHM809
      kabellengte: 30 cm Nominal current: 1,7 A
      https://www.123-3d.nl/123-3D-NEMA17-HR-stappenmotor-hoge-resolutie-0-9-graden-per-stap-4-0-kg-cm-42BYGHM809-i68-t14804.html

      This becomes even more important for the new printer I am designing since it'll have 3 700mm ball screws. with 3 motors each with their own driver. This setup will however have auto bed calibration, but still.

      1 Reply Last reply Reply Quote 0
      • dc42undefined
        dc42 administrators
        last edited by

        You could use the following at/near the end of config.g:

        G91
        G1 S2 Z0.01
        G90

        This commands the Z axis to move up 0.01mm (any amount that corresponds to at least one microstep will do).

        If your E1 motor output is free, take a look at https://duet3d.dozuki.com/Wiki/Bed_levelling_using_multiple_independent_Z_motors.

        Duet WiFi hardware designer and firmware engineer
        Please do not ask me for Duet support via PM or email, use the forum
        http://www.escher3d.com, https://miscsolutions.wordpress.com

        Nemesisundefined 1 Reply Last reply Reply Quote 0
        • Nemesisundefined
          Nemesis
          last edited by

          I'll try that. I did notice that after a print completes there is no idle holding torque as well?

          Is this by design? I would assume IDLE hold torque is there whenever the motor isn't moving.

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

            @nemesis Do you have something in your end print Gcode that turns off the motors? Or do you have your idle current percentage set too low?

            Z-Bot CoreXY Build | Thingiverse Profile

            Nemesisundefined 1 Reply Last reply Reply Quote 0
            • Nemesisundefined
              Nemesis @Phaedrux
              last edited by

              @phaedrux Ah yeah I had M84 at the end 😅

              Removed it and now it has been resolved. Thnx!

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              • Nemesisundefined
                Nemesis @dc42
                last edited by Nemesis

                @dc42 said in No Z idle torque before Z move commands have been send:

                G91
                G1 S2 Z0.01
                G90

                Thnx this works brilliantly 🙂

                I did change it to (to make sure when I restart after power outage it's always exactly where it left off):
                G91
                G1 S2 Z0.01
                G1 S2 Z-0.01
                G90

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