G91                 	;Set to Relative Positioning
G1 H1 Z-600 F6000	;Move Z rail to limit switch until pressed
G1 H2 Z3 F250   	;Back off Z rail from limit switch a small amount
G1 H1 Z-10 F150   	;Move Z rail to limit switch slowly

G1 H1 X500 Y-500 F3000	;Move X and Y rail to limit switch until pressed
G1 H2 X-3 Y3 F250   	;Back off X and Y rail from limit switch a small amount
G1 H1 X10 Y-10 F150   	;Move X and Y rail to limit switch slowly
G90			;Absolute position