Z homing question

medicusdkfz

Is there a difference between

#1:
G31 K1 P500 X0 Y0 Z0
G30 K1 -> above the probing pin without G92 Z0

and #2:
G31 K1 P500 X0 Y0 Z0
G30 K1 Z-99999 -> above the probing pin
G92 Z0
?

The question is: Is G92 Z0 necessary for homing z?

fcwilt

Is there a difference between

#1:
G31 K1 P500 X0 Y0 Z0
G30 K1 -> above the probing pin without G92 Z0

and #2:
G31 K1 P500 X0 Y0 Z0
G30 K1 Z-99999 -> above the probing pin
G92 Z0
?

The question is: Is G92 Z0 necessary for homing z?

G92 Z0 sets the current logical Z position to 0 thus overriding the result of the G30.

Questions:

do you actually have a G31 in your homing code?
do you actually have the Z-99999 in your homing code.

Frederick

medicusdkfz

; homez.g
; called to home the Z axis

; do nothing if XY is not homed yet
if !move.axes[0].homed || !move.axes[1].homed
    echo "XY are not homed yet. Aborting!"
    abort
;end if

M98 P"/macros/magprobe_get_status.g"

if global.magprobe_status = "docked"
	M98 P"/macros/goto_z_switch.g"		    ; Goes over the Z-Switch PIN !!!! CHECK COORDINATES CAREFULLY !!!!
	G30 K1 Z-99999						    ; Probe the Z pin at the back
	G90
	G1 Z10 F9000
elif global.magprobe_status = "attached"
	M98 P"/macros/magprobe_dock.g"
	M98 P"/macros/goto_z_switch.g"		    ; Goes over the Z-Switch PIN !!!! CHECK COORDINATES CAREFULLY !!!!
	G30 K1 Z-99999						    ; Probe the Z pin at the back
	G90
	G1 Z10 F9000
else
	echo "Magprobe-status not detected. Aborting!"
	abort

This is my homez.g... I mentioned G31 for a better understanding. I guess, the trigger point of the probe will be set to the z-parameter in G31. In my case to 0 or to an offset...