(SETUP IN UNIT mm.)
G21

(OFFSET ZERO AT Z AIXS) 
G92 Z0

(MOVE Z GENTRY DOWN 20 mm. as speed 50 mm/min for PROBE sensor )
G38.2 Z-20 F50

(IF TUCH SENSOR RE OFFSET Z AS 19.969(DETUM SENSOR))
G92    Z19.969

(MOVE Z GENTRY UP AT position 25 mm. AS speed 100 mm/min)
G1 Z25 F100

(STOP MOVE)
M30