
14. Coordinates System Setting Functions
14.7 Reference (Zero) Position Return
512
Detailed description
(1) The G28 command is equivalent to the following:
G00 Xx
1
Yy
1
Zz
1
α
α
1
;
G00 Xx
3
Yy
3
Zz
3
α
α
3
;
In this case, x
3
, y
3
, z
3
and
α
3
are the reference position coordinates and they are set by a
parameter "#2037 G53ofs" as the distance from the zero point of the basic machine coordinate
system.
(2) After the power has been switched on, the axes which have not been subject to manual
reference (zero) position are returned by the dog type of return just as with the manual type. In
this case, the return direction is regarded as the command sign direction. If the return type is
straight-type return, the return direction will not be checked. For the second and subsequence
returns, the return is made at high speed to the reference (zero) position which was stored at
the first time and the direction is not checked.
(3) When reference (zero) position return is completed, the zero point arrival output signal is
output and also #1 appears at the axis name line on the setting and display unit screen.
(4) The G29 command is equivalent to the following:
G00 Xx
1
Yy
1
Zz
1
α
α
1
;
G00 Xx
2
Yy
2
Zz
2
α
α
2
;
Rapid traverse (non-interpolation type) applies
independently for each axis for the positioning from the
reference position to the intermediate point.
In this case, x
1
, y
1
, z
1
and
α
1
are the coordinates of the G28 or G30 intermediate point.
(5) Program error (P430) results when G29 is executed if automatic reference (zero) position
return (G28) is not performed after the power has been switched on.
(6) When the Z axis is canceled, the movement of the Z axis to the intermediate point will be
ignored, and only the position display for the following positioning will be executed. (The
machine itself will not move.)
(7) The intermediate point coordinates (x
1
, y
1
, z
1
,
α
1
) of the positioning point are assigned by the
position command modal. (G90, G91).
(8) G29 is valid for either G28 or G30 but the commanded axes are positioned after a return has
been made to the latest intermediate point.
(9) The tool compensation will be canceled during reference position return unless it is already
canceled, and the compensation amount will be cleared.