tool_probing.ngc

o<first-tool> sub
G90 G53 G0 Z0
G53 G0 X0 Y0
G91 G38.3 Z-180 F500
G38.5 Z10 F15
#1000=#5063
G90 G53 G0 Z100
G90 G53 G0 X50 Y50
o<first-tool> endsub
M02

first-tool.ngc should be in nc-files dir.

example: o<touchoff> call [0.080] [0.02][0.06] 

o<touchoff> sub
(#1 pierce height, #2 pierce delay, #3 cut height)
F10
G38.2 Z-1.75 (Probe to find the surface)
G91
G1 Z0.070 (Raise up to Z0)
G90
G92 Z0 (Set Z0)
G1 Z#1
M3 S1
M66 P0 L1 Q5 (Wait for Arc OK from Torch)
G4 P#2 (Pause for pierce delay)
F25
Z#3 (goto cut height)
o<touchoff> endsub
M2

another example:
o<auto-tool-change> sub
G90 G53 G0 Z0
G90 G53 G0 X0 Y0
G91 G38.3 Z-100 F500
G91 G38.5 Z10 F15
G43.1 k[#5063-#1000]
G90 G53 G0 Z0
G90 G53 G0 X50 Y50
o<auto-tool-change> endsub
M02