I'm converting a 3d Systems CubeX Trio to run with a rumba board running marlin with the minimum amount of hardware changes as possible. I have just about everything set up but I'm getting stuck trying to configure the z endstop. The CubeX Trio uses hall effect sensors to sense steel pieces on a predominately aluminum frame. The x and y axis work fine as the hall effect sensors and steel pieces are on the axis and work basically the same way as any mechanical endstop would. For the z endstop howerver, the sensor is located on the extruder head and the steel piece is located at a certain x,y position in the print bed. To get the sensor to trigger, the print head has to be at a certain x,y coordinate before moving the z axis so the sensor is over the steel piece is aligned with the sensor. attached is a quick sketch of the setup. I've been going over the config.h file to see if there is any sort of option to set this up, however if its there, I'm missing it. My other thought would be to change the g code interpreter for the command to home the z axis to first home the x and y then move to the coordinate that the steel piece is located at.
Is there an option in the Config file to make the printer do this? If I want to change the gcode, how would I do this.
If there's any better ideas on how to implement this short of machining a new piece to preposition the sensor, they would be welcome.