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    Dual Z-axis endstops

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    • rpolteraundefined
      rpoltera
      last edited by

      Yes I saw the post have that working but would like to get my NPN probe back eventually if possible.

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      • dc42undefined
        dc42 administrators
        last edited by

        If you mean that you can't connect your NPN probe to the E0 endstop connector because it is used for the second Z homing switch, you can connect your NPN probe to E1 endstop connector or to the Z probe connector instead if you select the appropriate probe type in your M558 command.

        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

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        • stripsundefined
          strips
          last edited by

          I got this working fine and will post my setup here soon. There is some oddities when lowering Z after hitting the endstops and only one axis move if I do not add S2 as instructed by David. I did report this as an bug on github as it seems it should not behave like that.

          https://github.com/dc42/RepRapFirmware/issues/91

          strips created this issue in dc42/RepRapFirmware

          closed Inconsistency in dual Z axis movements #91

          Ender 5 Plus, E3D Bigbox Dual

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          • guy_bc3dundefined
            guy_bc3d
            last edited by

            I'm working on a big IDEX build. Would the method you guys have described here also work for a Y axis using 2 steppers? It could be nice to tram the X axis at the start of a build.

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            • dc42undefined
              dc42 administrators
              last edited by

              Yes it should be possible to use dual Y homing switches in the same way.

              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

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              • stripsundefined
                strips
                last edited by

                Having fiddled with dual Z now for a while I'm not to fond of the extra axis in the UI. Z controls both Z motors but U only controls the one. How can I hide the U axis or at least disable it so I don't accidentally move only one Z motor?

                Pretty easy to hit U instead of Z

                Ender 5 Plus, E3D Bigbox Dual

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                • dc42undefined
                  dc42 administrators
                  last edited by

                  I can think of two potential solutions, both requiring firmware changes:

                  1. Implement support for multiple Z homing switches directly in firmware, so you don't need to configure additional axes. This is what I had planned before I realised that you could do it using additional axes.

                  2. Add a facility to specify a number of displayed axes that is lower than the total number of configured axes.

                  In the meantime, you could avoid the risk of moving only one Z axis by mapping the U axis to a non-existent motor except during Z homing

                  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

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                  • efficientAFundefined
                    efficientAF
                    last edited by

                    Are there any updates to official firmware that has support for this? If not, would it be possible to use a macro to temporarily reassign drivers, home both sides, then revert back to the assignments in config.g (or manually copy and paste those settings into the macro)?

                    I'm hoping to avoid the need to have extra axes controls that can be messed with on accident or the need to mod the firmware to mitigate this. Plus, I only intend to perform this action once at startup, not before each print since I want to level my gantry and let my probe handle normal homing. Once current is applied to the motors I shouldn't need to do this again.

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                    • dc42undefined
                      dc42 administrators
                      last edited by

                      Firmware 1.19beta6 will support hidden axes. So you will be able to use the U axis for the second motor during homing, but the user interface will not provide a Home U button, nor jog controls for the U axis.

                      The firmware changes for this are already implemented, but not tested yet.

                      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

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                      • efficientAFundefined
                        efficientAF
                        last edited by

                        Marvelous! I think I'm on 1.17 so I'm due for an update! I only see the beta5 on github, is there somewhere I can get the latest? Is there any documentation on the new functionality and how to setup?

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                        • dc42undefined
                          dc42 administrators
                          last edited by

                          1.19beta6 will be released when I have tested it. The M584 command has a new optional parameter P which specifies the maximum number of visible axes. So if you use M584 to create a U axis but also specify P3 in that command then the U axis will be hidden.

                          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

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                          • efficientAFundefined
                            efficientAF
                            last edited by

                            Ahh, I'll keep an eye out for that and let you know if I have any questions, thanks David!

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                            • dintidundefined
                              dintid
                              last edited by

                              Is the dual Z-endstops implemented, or going to be implemented in 1.19, or do we use the solution you outlined below?

                              I'm homing to Z-max using 2 independent motors and want them to "sync up" when homing, as all sorts of things can happen to make them go out of sync.

                              @dc42:

                              I expect to implement multiple Z homing switches in firmware 1.19. In the meantime I think you can achieve the same thing as follows:

                              1. Put this command in config.g:

                              M584 X0 Y1 Z2:3 U3 E4

                              This assigns your second Z motor (connected to the E0 motor output) to both the Z and U axes.

                              2. In your homez.g file, do this:

                              M584 Z2
                              G1 S1 Zxxx Uxxx
                              G92 Zxxx
                              M584 Z2:3

                              This splits Z into the Z and U axes, homes them simultaneously, and then restores normal Z movement. Fill in the xxx values to suit your machine - see https://duet3d.com/wiki/Configuring_RepRapFirmware_for_a_Cartesian_printer#Homing_files.

                              3. Change the Z homing section of homeall.g to do the same.

                              4. Connect the second Z endstop switch (the one you use for the U motor) to the E0 endstop input.

                              Test the above carefully, with low motor current and a hand on the power switch, in case I have forgotten something.

                              RepRapFirmware supported G-codes: https://duet3d.com/wiki/G-code

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                              • dc42undefined
                                dc42 administrators
                                last edited by

                                The advice remains the same for now, except the detail has changed. I now suggest the following:

                                1. Put this command in config.g:

                                M584 X0 Y1 Z2:3 U9 E4 P3

                                This assigns your second Z motor (connected to the E0 motor output) to the Z axis, and creates a U axis that uses driver 9 (which I am assuming is not connected to any motor). The P3 parameter limits the number of visible axes to 3 in firmware 1.19beta6 and later, so that the U axis is not visible in the user interface.

                                2. In your homez.g file, do this:

                                M584 Z2 U3
                                G1 S1 Zxxx Uxxx
                                G92 Zxxx
                                M584 Z2:3 U9

                                Assuming that driver 9 is not connected, assigning the U axis to it other than during Z homing prevents inadvertent movement of the U motor if a G1 command with a U parameter is executed.

                                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

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                                • dintidundefined
                                  dintid
                                  last edited by

                                  Thanks.
                                  I Just need to add some config to make it go back from z-max (where my bed is homing currently) to z-min and use a probe to get the right distance from nozzle to bed 🙂

                                  RepRapFirmware supported G-codes: https://duet3d.com/wiki/G-code

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                                  • SpeedyDadundefined
                                    SpeedyDad
                                    last edited by

                                    This may be a stupid question but when doing this, I assume you move the extruder to the E1 connector?

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                                    • dc42undefined
                                      dc42 administrators
                                      last edited by

                                      @SpeedyDad:

                                      This may be a stupid question but when doing this, I assume you move the extruder to the E1 connector?

                                      You can either use the E0 motor output for the second Z motor and E1 for the extruder (which is what I assumed in the config examples I gave above), or vice versa. Just tell the firmware which way round you have them in the M584 command.

                                      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

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                                      • SpeedyDadundefined
                                        SpeedyDad
                                        last edited by

                                        Thanks

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                                        • FrankNPrinterundefined
                                          FrankNPrinter
                                          last edited by

                                          yes there are several FT5 owners running dual home z. I am still waiting to see if going to 1 z motor and linking the 2 z axis would be a better option. I have Duet WIFI so if i don't, i will eatu p my extra extruder spot if I split Z. In series you only get half the power any way so not sure if there is an up side to 2 motors in series? I know we talked about that briefly, your thoughts are always appreciated DC42! (https://www.youtube.com/watch?v=askVj4_5f9c)

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                                          • dc42undefined
                                            dc42 administrators
                                            last edited by

                                            If you connect two Z motors in series, you don't lose torque at low speeds. Each provides the same torque that a single motor would at the same current setting. However, the maximum speed you can run the motors at before the torque starts dropping is halved. This isn't normally a problem because high Z speeds are not required.

                                            Firmware 1.19beta9 includes most of the implementation of bed leveling using multiple Z motors connected to individual drivers.

                                            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

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