External Stepper Drivers on a DUET 2 Wifi - Help



  • Hi

    I am currently designing a large scale 3D printer and was looking at the DUET 2 Wifi board and DUEX 5 Externder board. Given the size of the printer i have been looking at larger stepper motor than the board and extender board supports and i therefore wants to ask.

    Is it possible to output the digital clock and direction signal from the board before it enters the stepper motor driver, and from there send the signal to an external motor driver?

    If not, is there a way to convert the output from the stepper driver (2-coil signal) back to the digital clock and direction signal?

    I hope some here can help me, since i am not that strong in electronics.

    Best regards
    Andreas Eplov, Zenvo Automotive.


  • administrators

    To use external drivers, you should connect them to the 7 sets of step/direction/enable outputs provided on the expansion connector and on the CONN_LCD port. We recommend using the expansion breakout board https://www.duet3d.com/DuetAddons/Expansion_Breakout which boost the voltage and current available for the 5 sets on the expansion connector.



  • Thank you very much. Would this breakout board be possible to use with your DUEX 5 board also, or does it use the same expansion port?


  • administrators

    @eplov said in External Stepper Drivers on a DUET 2 Wifi - Help:

    Thank you very much. Would this breakout board be possible to use with your DUEX 5 board also, or does it use the same expansion port?

    It uses the same expansion port. We plan to produce a DueX0, which will be like a DueX5 but with buffers for external drivers instead of the TMC2660 drivers; but it's not available yet. Meanwhile, it's possible to use both the expansion breakout board and a DueX2 if you make up a ribbon cable with 3 connectors, but you will only be able to use the last 3 of the external drive connectors on the breakout board, because the first 2 sets of ste/dir/CS signals will be used by the two TMC2660 on the DueX2.

    If your requirement is to drive Nema 23 motors, then if you choose them carefully, the Duet WiFi/Ethernet can drive them directly.



  • We are looking at NEMA 34 motors, so there shouldn't be any possibility of running it directly off the board.

    Just to be sure i understand everything correctly. If we use the breakout board, there is no way of getting more than five stepper motors running, given that the breakout board only use the five controllers coming from the DUET3D 2 Wifi.

    The problem is that we need at least seven motors to make what we really want. Three could be sufficient but not desirable.



  • I got it now. Two external from the CONN_LCD and additional five from the breakout board.

    Thank you very much for the help.

    This gives us seven digital signal to run through an external stepper driver.
    If this is the case does that eliminate the five stepper drivers already present on the board, i.e only opening up for seven, or is it possible to run two external using the CONN_LCD, five external on the breakout board and five internal on the board?


  • administrators

    @eplov said in External Stepper Drivers on a DUET 2 Wifi - Help:

    or is it possible to run two external using the CONN_LCD, five external on the breakout board and five internal on the board?

    Yes you can do that.

    Is this a one-off machine, or something you plan to replicate? If you plan to replicate it, then the Duet 3 series may be a better bet because it can drive Nema 34 motors directly. We demonstrated that at the TCT show last year.



  • @dc42 It is a one off unit. We are gonna design it with a build volume of minimum 2000x2000x1500mm. So i do not think we will need another printer of this size.



  • @dc42

    Any news on the DueX0?

    I've got an application which it would be very helpful to have, just wondering if I can skip working on a workaround.

    If the board design is ready, I could have it fabbed if needed for my purposes, or could help you out with beta testing.

    Thanks,
    Tim


 

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