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Additional Micro Limit Switches

Discussion in 'General Electronics' started by CDNSmitty, Apr 21, 2020.

  1. CDNSmitty

    CDNSmitty New
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    Is there room (a way in general) to add 2 additional micro limit switches in the rear Y axis (back side) and right side or X? I have a OB lead 1010 and find that I would like to add them to the exisitng 3 I have which came with the CNC. I have the black box motion controller.

    Chris
     
  2. Peter Van Der Walt

    Peter Van Der Walt OpenBuilds Team
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    Depends which - we have two kinds:

    Xtension Limit Switch Kit or Micro Limit Switch Kit

    We highly recommend the Xtension limits - if you havent got the upgrade yet, worth spoiling yourself a little! (onboard RC noise filters, easier wiring with Xtension Wiring ecosystem, onboard LED, etc

    With the Xtensions its as simple as joining
    • GND on BlackBox connector to GND on first switch, to GND on second switch
    • V+ on BlackBox connector to V+ on first switch, to V+ on second switch
    • SIG on BlackBox connector to SIG on first switch, to SIG on second switch
    Simple and easy right?

    If you don't have the Xtension Limits, refer to https://github.com/gnea/grbl/wiki/Wiring-Limit-Switches (Signal input works the same as with an Arduino)
     
  3. CDNSmitty

    CDNSmitty New
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    Oh yes I meant I have those xtension limit switches. The 3 standard ones came with my Lead 1010. I just don't see that I have anymore spots to plug additional ones in. I have to look at the black box again. My issue is that I don't like accidentally running the gantry all the way back, hitting the end and throwing it out of square. It's an easy fix. I power down and measure distances then adjust. I just don't what kind of damage I'm doing when that happens. Also would like to run a pencil around the full area where it auto stops from the switch. I wonder what actual live area I have to work with. So far I think it measures 30" Y and 28" X. The limit switches would give me peace of mind.
     
  4. CDNSmitty

    CDNSmitty New
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    Wait. Ami I reading your instructions correctly? Can I daisy chain the switches?
     
  5. Alex Chambers

    Alex Chambers Master
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    Yes. The Xtension limit switches are normally open - wire them in parallel.
    Alex.
     
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  6. CDNSmitty

    CDNSmitty New
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    This is what I have. Green tape are labels.
     

    Attached Files:

  7. Peter Van Der Walt

    Peter Van Der Walt OpenBuilds Team
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    Tecnically thats something different.

    Just a case of sticking two wires in the same hole, and all the same labelled pins on the same line down to controller. I tend to wire from first switch to second switch, and from first switch to controller (rather than extra wire from controller to each switch, waste of a run for me)
     
  8. CDNSmitty

    CDNSmitty New
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    Perfect. Thanks everyone for helping me out.
     
  9. fathmi

    fathmi New
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    Can anyone please share an image of how two wires are connected in 1st switch (one incoming from controller and other outgoing to 2nd switch) ? I will be using one for Y axis and other for Y2 axis for squaring both Y axes.
     
    #9 fathmi, Jan 16, 2021
    Last edited: Jan 17, 2021
  10. Peter Van Der Walt

    Peter Van Der Walt OpenBuilds Team
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    Probably wont need a picture :) twist the two wirea together, stick em in the terminal and tighten. Easy. Just make sure its neat, no uninsulated wires hanging outside the terminal that can short against each other (trim length down so it fits in just deep enough)
     
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  11. fathmi

    fathmi New
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    Thanks! Is the homing sequence of openbuilds Control going to take care of this sqauring Y axes I am trying to achieve, if I daisy chain these Y and Y2?
     
    #11 fathmi, Jan 17, 2021
    Last edited: Jan 17, 2021
  12. Peter Van Der Walt

    Peter Van Der Walt OpenBuilds Team
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    No autosquaring is something different entirely. See docs:blackbox:jumper-slaveaxis [OpenBuilds Documentation]

    It is a total schlep and not worth doing in our opinion. Build the machine square, much better than working around a badly built machine with software. We tested the feature a lot when it came out and its harder to adjust the switches for square than it is to build the frame square instead.

    If you do want to use it you have to recompile Grbl with that feature enabled, set the jumpers, and wire Y2 limits switch in parallel with Z (as Y input is used for Y1) - this is explained in the Grbl source code where you enable the feature.

    But ultimately, not worth it.
     
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  13. fathmi

    fathmi New
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    I agree if it takes that much effort, worth spending time on producting something instead. Thanks for the headsup.
     
    Peter Van Der Walt likes this.

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