Connecting Duet Wifi to Delta Printer : Steppers shaking, not turning

  • Hello @DC42,

    I have just built a new delta printer, and I decided to use a 3A/12V power supply and these bipolar steppers:

    The steppers come pre-wired Red-Green-Yellow-Blue ( 1B-1A-2A-2B ). I set M906 to 1200 ( 1.2A ) to derate the amperage by 80% on the stepper. The firmware has been compiled and configured for Delta operation. The endstops are the usual 3.3v makerbot-style mechanical endstops at the top of the towers.

    When I click the "Home" button on the PanelDue, all three steppers just shake violently and do not otherwise move or turn. I checked the stepper phase windings, and they are as the datasheet says they should be.

    Is there something obvious I have missed? Is there something else I need to set in G-Code?

    M350 is set to 16 step microstepping:

    Microstepping - X:16(on), Y:16(on), Z:16(on), E:16(on):16(on):16:16:16:16:16:16:16

    M906 is set to 1.2A for all towers:

    Motor current (mA) - X:1200, Y:1200, Z:1200, E:800:800:800:800:800:800:800:800:800, idle factor 60%

  • administrators

    If the steppers shake violently, that usually means that the phases are not connected correctly. Disconnect the motor cable from the Duet and check with a multimeter that where it plugs in to the Duet, the two wires at one end of the connector have continuity (with a few ohms resistance), and so do the two wires at the other end.

  • I confirmed that the phases are correctly wired via the "short the phase" test to see if I got resistance when turning the motor.

    I found out that my power supply was fading down to 9.4V under load, and replaced it. The steppers are now running smoothly.

    I also upgraded my duet wifi to firmware 1.20. I'm not sure what version of the PanelDue I have, so I haven't upgraded the paneldue yet… it seems to work fine though.

    I have a new issue, however. I'll start a new forum post to get your help debugging it.

  • administrators


    I found out that my power supply was fading down to 9.4V under load, and replaced it. The steppers are now running smoothly.

    Thanks, I'll bear that in mind next time someone reports similar symptoms. If the power voltage falls below 9.4V then the firmware turns the stepper drivers off and an under-voltage event is recorded, because the stepper drivers shut down at a slightly lower voltage. You can tell that this has happened by running M122 and looking for "under voltage events" in the report.


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