14. Coordinates System Setting Functions
14.7 Reference (Zero) Position Return
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14.7 Reference (Zero) Position Return; G28, G29
Function and purpose
(1) After the commanded axes have been positioned by G0, they are returned respectively at
rapid traverse to the first reference (zero) position when G28 is commanded.
(2) By commanding G29, the axes are first positioned independently at high speed to the G28 or
G30 intermediate point and then positioned by G0 at the commanded position.
Reference position
Machine zero point
(0,0,0,0)
G28
G28
G29
G29
G30
G30P3
G30P4
G30P2
(x
1
,y
1
,z
1
,
α
1
)
Intermediate point
(x
2
,y
2
,z
2
,
α
2
)
Start point
3rd reference position
4th reference position
(x
3
,y
3
,z
3
,
α
3
)
2nd reference position
Command format
G28 Xx
1
Yy
1
Zz
1
α
α
1
; Automatic reference position return
G29 Xx
2
Yy
2
Zz
2
α
α
2
; Start position return
α
α
1
/
α
α
2
: additional axis