Duet and external Stepper Motor controller



  • Is it possible to tap onto the existing stepper motor signals on the board - for example - X axis - tap onto the step,direction and enable signal and use those signals to drive the step and direction inputs on a stepper motor amplifier controller such as units made by automation direct or Yamaha then let the amplifier control the large stepper motors etc. i saw there is a breakout board but being new to 3D printers and no experience with Gcode trying to tap onto the existing step,direction etc. signals and advoid having to make any modifications in Gcode. Thanks


  • administrators

    The correct way to use external stepper drivers is to use the 5 sets of stepper driver control pins on the expansion connector, either directly or using the stepper expansion breakout board. There are another 2 sets on the CONN_S connector.

    You do not need to make any modifications to the GCode files that you want to print, you just need to modify the config.g file on the SD card to tell it to use the external drivers for the axes concerned instead of the internal ones.



  • Thanks
    Ordering everything today so hope to start playing with it soon. Looked through documentation. Is there a section that describes how to modify the config file to reassign the x,y,z to the breakout board external drivers.



  • Great documentation. Just have to take the time to read it but seems like the way this is set up it gives the person all kinds of control. Not knowing G code and looking through the G code section to try and undertand how i would reassign the x,y,z motors to external drivers on the breakout board. Think i now understand. you have to edit the G code.
    M569 set motor configurations
    M584 set drive mapping.
    Am i see this correctly, or is there a easier way to do it. At the moment since i am learning and figured its best to go the 32 bit type board route, i would use Reprapfirmware configuration tool to do this.
    Thanks to Tony for answering all of my newbie dumb questions.


  • administrators

    @irondesk40 said in Duet and external Stepper Motor controller:

    M569 set motor configurations
    M584 set drive mapping.

    That's correct. M569 to extend the step pulse timing for the external drivers (T parameter) and if necessary invert the enable signal (R parameter). M584 to remap the axes to the external drivers. Example:

    M569 P5 T2 ; increase driver 5 timing to 2us
    M569 P6 T2 ; increase driver 6 timing to 2us
    M569 P7 T2 ; increase driver 7 timing to 2us
    M584 X5 Y6 Z7 ; remap XYZ axes to external drivers 567

    The online configuration tool does not yet support axis remapping; so after generating files using the configurator and uploading them to the Duet, go to the System Editor page of Duet web Control and edit the config.g file there.


 

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