FANUC Series 16/18/160/180-Model C Machining Center Operators Manual

PROGRAMMING
B–62764EN/01
6. REFERENCE POSITION
105
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)
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
III–3.1) is made. The G30 command is generally used when the automatic
tool changer (ATC) position differs from the reference position.
In general, it is commanded immediately following the G28 command or
G30. For incremental programming, the command value specifies the
incremental value from the intermediate point.
Positioning to the intermediate or reference points are performed at the
rapid traverse rate of each axis.
When the workpiece coordinate system is changed after the tool reaches
the reference position through the intermediate point by the G28
command, the intermediate point also shifts to a new coordinate system.
If G29 is then commanded, the tool moves to to the commanded position
through the intermediate point which has been shifted to the new
coordinate system.
The same operations are performed also for G30 commands.
G27 command positions the tool at rapid traverse rate. If the tool reaches
the reference position, the reference position return lamp lights up.
However, if the position reached by the tool is not the reference position,
an alarm (No. 092) is displayed.
Before a machine coordinate system is established with the first reference
position return after power–on, the manual and automatic reference
position return feedrates and automatic rapid traverse rate conform to the
setting of parameter No. 1428 for each axis. Even after a machine
coordinate system is established lupon the completion of reference
position return, the manual reference postiion return feedrate conforms to
the setting of the parameter.

D Reference position
return (G28)
D 2nd, 3rd, and 4th
reference position return
(G30)
D Return from the
reference position (G29)
D Reference position
return check (G27)
D Setting of the reference
position return feedrate

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