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Introduction

This example shows how to add one external stepper driver to drive a third extruder on a Duet 2 Wifi using the E2 pin connectors. Guide originally written by user Exerqtor. https://forum.duet3d.com/topic/6732/exte...

  1. On the Duet 2 Wifi  and Ethernet these are the pins you need to connect to (text highlighted yellow): A custom cable must then be made that connects these pins to the breakout board:
    • On the Duet 2 Wifi and Ethernet these are the pins you need to connect to (text highlighted yellow):

    • A custom cable must then be made that connects these pins to the breakout board:

  2. Now we need to wire up our external driver breakout board. 3.3V and GND (Note: The pin labelled 5V on the breakout board must be connected to 3.3V on the Duet, not 5V!)
    • Now we need to wire up our external driver breakout board.

    • 3.3V and GND (Note: The pin labelled 5V on the breakout board must be connected to 3.3V on the Duet, not 5V!)

    • 12V/24V (vin) and GND

    • ESDG wires (Enable, Step, Direction, Ground)

    • Note: It’s strongly recommend clearly marking your wires, so as not to short out something or otherwise plug them in improperly!

  3. The generation2 Duets also support two additional drivers connected to the CONN_LCD connector.
    • The generation2 Duets also support two additional drivers connected to the CONN_LCD connector.

    • A custom cable must be made to connect the pins on the CONN_LCD and the breakout board as if you were to use the Expansion header.

  4. Which Expansion you want to use for your purpose is pretty much up to you, do what suits your needs best. You just have to adapt RepRapFirmware accordingly.
    • Which Expansion you want to use for your purpose is pretty much up to you, do what suits your needs best. You just have to adapt RepRapFirmware accordingly.

    • To use external drivers to drive X, Y and/or Z axes instead of the internal ones, you need to remap the X/Y/Z axis to the external driver. The drive numbers are shown in the picture.To remap the X, Y or Z motors to external drivers in RepRapFirmware 1,14 or later, use the M584 command.

    • Configuring the Enable polarity and step timing The Enable signals on the expansion connector are active low by default but you can change this using the R parameter in the M569 command. You can also set a minimum step pulse width and other timings in the M569 command using the T parameter; try 1us to 4us when using external drivers.

    • M584_Set_drive_mapping: Gcode

    • M569_Set_motor_driver_direction Gcode

  5. The orientation of the drivers is really important. You are going to fry the drivers if they are inserted incorrectly. Remember to always have all power turned off, that includes any USB, whenever you handle the drivers - aside from adjusting the vref.
    • The orientation of the drivers is really important. You are going to fry the drivers if they are inserted incorrectly. Remember to always have all power turned off, that includes any USB, whenever you handle the drivers - aside from adjusting the vref.

    • The A4988 is inserted with trimpot facing away from dipswitches.

    • The DRV8825 is inserted with trimpot facing towards the dipswitches.

    • SilentStepStick TMC2100 is inserted with trimpot facing towards the dipswitches.

  6. This is not about what value to set it at, but about a good practice to avoid accidents. Use 2 clamps on your Multimeter.
    • This is not about what value to set it at, but about a good practice to avoid accidents. Use 2 clamps on your Multimeter.

    • Connect the black one to a GND on your printer. Easy to use is directly from PSU or from a GND from endstop pins.

    • Attach the red one to a small screw-driver fitting for your trimpot.

    • This way you have your hands free to actually adjust the trimpot and not having to hold multiple wires and worry about something slipping and making a short circuit somewhere:

  7. For many external drivers the wiring is simplified by using the Duet Expansion Breakout Board. This provides differential signals for up to 5 step/dir/enable connections for external stepper drivers.
    • For many external drivers the wiring is simplified by using the Duet Expansion Breakout Board. This provides differential signals for up to 5 step/dir/enable connections for external stepper drivers.

Finish Line

3 other people completed this guide.

Jason Znack

Member since: 06/16/2018

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