
B-63784EN/01 PROGRAMMING 6.REFERENCE POSITION
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- Reference position return check
The reference position return check (G27) is the function which checks
whether the tool has correctly returned to the reference position as
specified in the program. If the tool has correctly returned to the
reference position along a specified axis, the lamp for the axis goes on.
Format
- Reference position return
G28 IP ; Reference position return
G30 P2 IP 2nd reference position return
(P2 can be omitted.)
G30 P3 IP ; 3rd reference position return
G30 P4 IP ; 4th reference position return
IP: Command specifying the intermediate position
(Absolute/incremental command)
- Return from reference position
G29 IP ;
IP: Command specifying the destination of return from
reference position
(Absolute/incremental command)
- Reference position return check
G27 IP ;
IP: Command specifying the reference position
(Absolute/incremental command)
Explanation
- Reference position return (G28)
Positioning to the intermediate or reference positions are performed at
the rapid traverse rate of each axis.
Therefore, for safety, the cutter compensation, and tool length
compensation should be cancelled before executing this command.
The coordinates for the intermediate position are stored in the CNC
only for the axes for which a value is specified in a G28 block. For the
other axes, the previously specified coordinates are used.
(Example) N1 G28 X40.0 ; Intermediate position (X40.0)
N2 G28 Y60.0 ; Intermediate position (X40.0, Y60.0)
- 2nd, 3rd, and 4th reference position return (G30)
In a system without an absolute-position detector, the first, third, and
fourth reference position return functions can be used only after the
reference position return (G28) or manual reference position return
(See Operation II-3.1) is made. The G30 command is generally used
when the automatic tool changer (ATC) position differs from the
reference position.