Duet3D Logo Duet3D
    • Tags
    • Documentation
    • Order
    • Register
    • Login

    Mini 5+ with 3HC Expansion for XY steppers in a CoreXY printer?

    Scheduled Pinned Locked Moved
    Using Duet Controllers
    4
    9
    385
    Loading More Posts
    • Oldest to Newest
    • Newest to Oldest
    • Most Votes
    Reply
    • Reply as topic
    Log in to reply
    This topic has been deleted. Only users with topic management privileges can see it.
    • mjwatersundefined
      mjwaters
      last edited by

      Hello,

      I am building a CoreXY printer and would like to use a Duet 3 Expansion 3HC to drive large XY steppers. I'd prefer to use the 3HC expansion with Duet 3 Mini 5+ rather than the Duet 3 6HC because I'd like to have built-in Wifi and I only need two high current drivers.

      I am new to Duet hardware. So I am asking: Is there any reason that this configuration wouldn't work? I saw something about CAN bus latency but I don't know how much it might affect my application.

      If this is a bad idea, I'll buy the 6HC and a long Ethernet cable.

      Thanks,
      -Mike

      T3P3Tonyundefined dc42undefined 2 Replies Last reply Reply Quote 0
      • T3P3Tonyundefined
        T3P3Tony administrators @mjwaters
        last edited by

        @mjwaters There is no significant difference between step rates achievable between the 3HC and the 6HC. If the combination provides you all the IO you need an motor connections then it will work well.

        Wifi vs Ethernet depends on your wifi signal and contention from surrounding networks. the Wifi modules used on Duets are 2.4Ghz (not 5 Ghz) and deal less well than modern phones and laptops with congested environments and weak signals.

        www.duet3d.com

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

          @mjwaters yes that should work. Two points to note:

          • Stall detection is not yet implemented on CAN-connected boards, so you will need to use endstop switches for the X and Y axes
          • Currently it's best to drive the Z motor(s) from the main board, to get good results from a Z probe

          See https://duet3d.dozuki.com/Wiki/Duet_3_firmware_configuration_limitations for the current firmware limitations when using CAN-connected boards. We are gradually removing most of these limitations.

          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

          mjwatersundefined 2 Replies Last reply Reply Quote 0
          • mjwatersundefined
            mjwaters @T3P3Tony
            last edited by

            @t3p3tony

            That's an excellent point since I am in a WiFi congested area.

            Thanks!

            1 Reply Last reply Reply Quote 0
            • mjwatersundefined
              mjwaters @dc42
              last edited by

              @dc42

              • Limit switches were always part of the build plan since nobody here likes the startling noise of stepper stall!
              • Not a problem.

              Do you think the CAN latency will affect the XY accuracy if I use the 3HC expansion? What is the latency? from a print speed, we can estimate a position latency, right?

              BTW, the RatRig team also is curious my proposed configuration so I'll be forwarding them the details.

              Best,
              -Mike

              T3P3Tonyundefined 1 Reply Last reply Reply Quote 0
              • T3P3Tonyundefined
                T3P3Tony administrators @mjwaters
                last edited by T3P3Tony

                @mjwaters the moves are synchronised with the clock on the mainboard by recovering the timing signal from the can bus. they are sent ahead of time and then step generation is done on the expansion board and mainboard off the can bus clock signal. The CAN bus limits how many different boards can be addressed and what data rate, but not the synchronisation of the steps in a move in a latency sense.

                www.duet3d.com

                mjwatersundefined 1 Reply Last reply Reply Quote 0
                • mjwatersundefined
                  mjwaters @T3P3Tony
                  last edited by

                  @t3p3tony

                  That's very cool and sounds like it could have taken a fair amount of time to implement.

                  Alright, I am going to put in an order with your resellers today.

                  Thanks for all your help!

                  1 Reply Last reply Reply Quote 1
                  • mjwatersundefined
                    mjwaters @dc42
                    last edited by

                    @dc42

                    Hi again,

                    My printer is built, and I am debugging now. Do I need to have the extruder motor on the same board as the XY steppers? It seems like I might for them to be considered part of the same 'tool'.

                    P.S. I am loving my Duet hardware/software so far!

                    deckingmanundefined 1 Reply Last reply Reply Quote 0
                    • deckingmanundefined
                      deckingman @mjwaters
                      last edited by

                      @mjwaters said in Mini 5+ with 3HC Expansion for XY steppers in a CoreXY printer?:

                      @dc42

                      Hi again,

                      ......... Do I need to have the extruder motor on the same board as the XY steppers? .......

                      No that shouldn't be necessary. For info, my 6 extruders are on separate expansion boards to my XY and Z which are on a third expansion board and UVA and B axes which are connected to the main board.

                      Ian
                      https://somei3deas.wordpress.com/
                      https://www.youtube.com/@deckingman

                      1 Reply Last reply Reply Quote 1
                      • First post
                        Last post
                      Unless otherwise noted, all forum content is licensed under CC-BY-SA