MPCNC RAMPS Dual Endstop Wiring

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This topic contains 2 replies, has 2 voices, and was last updated by  Lindsay Fowler 12 months ago.

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  • #69240

    Lindsay Fowler
    Participant

    Hi All,

    Where do I wire in the end stop limit switches, please?

    On this page, the RAMPs picture is missing:https://www.v1engineering.com/auto-square-dual-endstops/

    There is a label on the Ramps board:

    End stops

    1 1 1 1 1 1
    S x-min x-max y-min y-max z-min z-max
    x-min x-max y-min y-max z-min z-max
    +

    I have filled in the table with the connections I think are right for Normally Closed with Marlin Dual End-stops.

    Is this correct?

    Thanks very much All.

     

    #69254

    Ryan
    Keymaster

    Yes that is correct, your board should be labeled and I have the chart directly next to the pictures.

    1 user thanked author for this post.
    #72916

    Lindsay Fowler
    Participant

    Update:

    When I asked I didn’t really understand, now I can see that diagram was just wrong, so in case anyone else is as confused as I was, here is a correct diagram of the Ramps 1.4 limit switch wiring that makes much more sense:

    Naturally each limit switch has two terminals, one terminal is connected to the S row, the other terminal is connected to the ground row.

    S (Signal) x1-min x2-min y1-min y2-min z-min      
    – (Ground) x1-min x2-min y1-min y2-min z-min
    +

     

    With Dual End-Stops you don’t get Max limits – there aren’t enough pins. So with Dual End-stops you sacrifice Max limits to gain a minium limit on each motor. Hence you will see “//#define MAX_SOFTWARE_ENDSTOPS” (which is commented out) in configuration.h

    To compensate for not having Maximum limit switches,  I think you can rely on software by setting the print bed size in configuration.h here:

    // The size of the print bed
    #define X_BED_SIZE 200
    #define Y_BED_SIZE 200

    Presumably, 200 is 200mm.

    I’m not sure yet what happens if your G-Code tells your machine to go beyond the BED_SIZE hopefully Marlin is smart enough to reject the instruction!

    I think I will wire in some max limit switches of my own to kill the machine if it ever actually hits the ends. Even if the software limits work, the machine is always susceptible to missing steps when pushed too hard and losing its position. So I’ll safeguard it simply by wiring all max-limit switches togther in parallel with the Kill button.

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