Core XY Homing position, what am I missing



  • I an trying to get my new Core XY build to home X- And Y- to be in the front left corner but no matter how I set the M569 directions I cannot seem to get it to home to that corner.
    Combinations I have tried:
    1st
    M569 P0 S1
    M569 P1 S1
    X moves in wrong direction but Y moves correct (X+ ←, Y+ ↑)

    2nd
    M569 P0 S0
    M569 P1 S0
    X moves in correct direction but Y moves in wrong direction (X+ →, Y+ ↓)

    3rd
    M569 P0 S1
    M569 P1 S0
    X moves in Y direction and Y moves in X direction (X+ ↑, Y+ ←)

    4th
    M569 P0 S0
    M569 P1 S1
    X moves in Y direction and Y moves in X direction but opposite from 3rd set (X+ ↓, Y+ →)

    What I am looking for is this (X+ →, Y+ ↑)



  • I don't understand how X can move right-left in your first two examples and forward-backward in the last two (and the opposite with Y).

    X and Y are directions, not motors.

    M569 P0 selects the A motor (plugged into the X motor driver on the controller board), M569 P1 selects the B motor (plugged into the Y motor driver on the controller board

    The extruder carriage usually moves left-right on the X axis guide rail(s). The whole X axis moves forward-backward on the Y axis guide rails.

    You have tried all four possible combinations of motion- there are none left to try. One of them should be correct.

    Where are the end-stops located?

    Did you tell the controller to use corexy kinematics (M667 S1)?

    Homing should drive the extruder carriage toward the endstops in both axes, regardless of where the printer's origin is located.

    See: https://drmrehorst.blogspot.com/2017/08/setting-up-corexy-printers-origin-and.html and https://drmrehorst.blogspot.com/2018/07/ummd-better-way-to-set-up-origin-and.html


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    @cdl1701yahoo-com said in Core XY Homing position, what am I missing:

    I an trying to get my new Core XY build to home X- And Y- to be in the front left corner but no matter how I set the M569 directions I cannot seem to get it to home to that corner.

    Swap the X and Y motor connections with each other.



  • @cdl1701yahoo-com From the wiki here https://duet3d.dozuki.com/Wiki/ConfiguringRepRapFirmwareCoreXYPrinter with both motors set to S0 do G91
    G1 S2 X10 F3000. Then quote:

    "If the head moves diagonally in the +X and +Y directions, all is well. If it moves in the -X and -Y directions, change the S parameter to S1 in the M569 P0 command. If it moves towards +X and -Y, or towards -X and +Y, turn the power off and swap the X and Y motor connections. "

    You have the latter case - (+X -Y) so turn the power off and swap the motor connectors.

    Edit. OOPs, I missed @dc42's post - he got there first.



  • OMG, it is always something so simple, actually I didn't think it mattered which motor went to which connector for the X & Y on a Core XY machine but that fixed it. Now I know.

    Thanks again guys.



  • @cdl1701yahoo-com said in Core XY Homing position, what am I missing:

    OMG, it is always something so simple, actually I didn't think it mattered which motor went to which connector for the X & Y on a Core XY machine but that fixed it. Now I know.

    Thanks again guys.

    Yes, it's a bit confusing because on a CoreXY, both motors contribute to pure X or pure Y moves so they don't actually have X and Y motors. They are often referred to as Alpha and Beta. I believe on the next generation Duet boards, the stepper drivers will simply be marked numerically, rather then X,Y, Z etc...


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