How to configure for origin at left REAR (not front) on a Cartesian printer?

I'm using Repetier firmware 0.92.9.  I have a custom cartesian printer with the origin in the left rear.  I see that Repetier expects it to be at the left front.  What do I need to change to get the firmware to know the Y origin is in the rear?  Everything currently works on the printer except that the Y axis prints the mirror image of what it should.  Do I just need to set the following 2 variables:
      INVERT_Y_DIR 1 
      Y_HOME_DIR 1 
Since Y_HOME_DIR 1 defines that the endstop is at the max, do I also need to physically connect the Y endstop switch on the controller board to the Y_Max terminals? 



  • Left rear is not possible with normal orientation of axis. You need to swap x and y motors and endstops and assign homing direction/max min endstop matching your printer. Left-right will then become x axis and back->front x axis. 
  • I found a configuration that works.  For all others that want to do this configuration, here's what I did:

    1. Assuming you have only min endstops, connect the Y endstop to the Y Max terminals on your control board.  The rest are firmware changes.
    2. Reconfigure endstops
      #define ENDSTOP_Y_MIN_INVERTING true
      #define MIN_HARDWARE_ENDSTOP_Y false
      #define ENDSTOP_Y_MAX_INVERTING true
      #define MAX_HARDWARE_ENDSTOP_Y true
    3. Reconfigure Y movements
      #define INVERT_Y_DIR 1
      #define Y_HOME_DIR 1

    You do NOT need to change the Y Min value
      #define Y_MIN_POS 0 // min still 0, but it is in the front of the printer now

    When you home the printer, it will be in the left rear at position x=0, y=Y_MAX, z=0, and it will print correctly.

  • You know that is not what you asked for:-) Origin = 0,0 in your solution is still left front only homing position is now left back! 

    I now assume that is what you really wanted, so well done!
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