2.8.11 AUTOMATIC RETURN TO REFERENCE
POINT (G28) (Cent’d)
Notes :
1. For parameter setting and other details of
the low traverse speed return motion shown
in Fig. 2.8.11.2, refer to 5.2.1 Manual Re-
turn to Reference Point.
2.
The starting point for RETURN TO REFER-
ENCE POINT motion must be in the area
shown in Fig. 2.8.11.4.
Fig.
2.8.11.3 can
be started from any position.
RETURN
DIRECTION
~ “’s
3. Before writing G28 in the program, cancel
the tool position offset as shown below .
a. Canceling in the preceding block
TU 1100 ;
G28 X.. . Z.. . :
b. Canceling in the block containg G28
G28 X.. . Z.. . TE~OO ;
4.
When G 28 is written with the tool position
offset or tool radius compensation on, the
offset or compensation is automatically can-
celled.
2,8.12 RETURN FROM REFERENCE POINT (G 29)
(1) With this function, the tool is positioned to
a specified point via the interim point, after
it has been once returned to the reference
zero point by the AUTOMATIC RETURN TO
REFERENCE ZERO COMMAND (G28) .
G28 X.. . Z.. . : Point A-+B+C
—“
(reference zero point)
Point B
G29 X.. Z.. . ;
Point C+B+D
Point D
-&
~
[REFERENCE ZERO POINT,
(2)
(3)
(4)
When G.29 is used, consideration on the dis-
tance between points B and C is unnecessary
in programming.
Especially when incremen-
tal instructions are used, this function is
useful to return the tool to the original co–
ordinate system after returning to the
reference zero.
Motions C + B and B + D are made simul-
taneously along the two axes in rapid trav-
erse. However, the tool will not move in
the direction for which instruction is omitted.
Where G28 is programmed several times,
the point B creat~d by the latest G28 in-
struction is effective for the motion by G 29.
EXAMPLE (absolute input)
Coordinates of interim
these two blocks.
N20 G28 X1O. z20.
point is equivalent to
‘z
;—G. 20. )
N25 G28 x30. ; —
(30. 20. )
l--r
N26 G29 x-40. z-50. ;
I
I I
u
GOO X30. Z20.
‘+--
GOO X-40. Z-50. ;
Notes :
1.
Commanding G 29 without the execution of
G28 after turning on the control constitutes
an error “059. “
2. In principle,
cancel tool offset before pro-
gramming G28 or G29. If they are program-
med while offset is effective, the interim
point B will be offset, and the tool will pass
point B’.
RETURN TO
REFERENCE ZERO
INTERIL! POINT
i
.4’.4
Fig, 2.17
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