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Motor and limit switch wiring w BB

Discussion in 'Controller Boards' started by WR_Rider, May 5, 2019.

  1. WR_Rider

    WR_Rider New

    Apr 3, 2019
    Likes Received:
    I purchased the "Xtension" limit switches to connect to the black box. However, I accidentally ordered 2 conductor wire instead of 3 conductor wire for them. Any reason I couldn't just wire the Xtention switches like micro switch per the instructions or is there something special about the Xtention switches that I should just order 3 conductor wire?

    2nd, I purchased non open build stepper motors. Will it matter which coil pair I connect to the "a" pair or "b" pair on the black box?

    Thank you for any input.
  2. Gary Caruso

    Gary Caruso OpenBuilds Team
    Staff Member Moderator Builder

    May 19, 2016
    Likes Received:
    If you use the two wire on the Xtension switches you just wont get the LED function on the switch board.
    Yes, any coil to A or B doesn't matter.
    Peter Van Der Walt likes this.
  3. NthAxisWorkshop


    Apr 11, 2018
    Likes Received:
    I'm pretty sure you can. I think the extra wire is for the LED indicator that comes on when triggered. If you don't mind not having any shiny bits at the end of your axes, two conductor should suffice. As for the wiring the steppers, if you switch the pairs, you may need to reverse the stepper directions in your GRBL config for the axis if it's headed in the wrong direction. Or like Gary said. :thumbsup:
    Peter Van Der Walt likes this.
  4. sharmstr

    sharmstr Master
    Moderator Builder

    Mar 23, 2018
    Likes Received:
    You can use 2 conductor wire. But I think maybe the led on them wont light up. Not sure on that, but I only have 2 wires going to mine.

    I have non OB motors on mine. As long as you know the which wires make a pair, it really doesnt matter how you wire them. If they are erratic, then you have your pairs wrong. If they move in the wrong direction, swap either A+ with A- or switch them in grbl config parameter $3.

    Stolen from Spark Concepts:
    • Simple verification of 4 wire stepper motors:
    1. Using a multi-meter, resistance Set the Ohmmeter to the lowest resistance scale.
    2. Attach one of the wires to the meter and, in turn, check each of the remaining three
    3. Mark the wire that gave a reading and mark the first wire you started with (coil A)
    4. The remaining two wires will be coil B
    NOTE: switching the polarity of either (one) coil will reverse the stepper's direction
  5. Peter Van Der Walt

    Peter Van Der Walt OpenBuilds Team
    Staff Member Moderator Resident Builder Project Maker Builder

    Mar 1, 2017
    Likes Received:
    2 wire: SIG and GND is important. The V+ pin is for LED and also for the onboard pullup resistor (so you loose a little noise immunity in 2 wire setup)
    sharmstr likes this.

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