Rockwell Automation 8520 9/Series CNC Lathe - Manual (Page 461)

Tool Control Functions
Chapter 20
20-5
Your system installer has the option in AMP to determine exactly when the
geometry and wear offsets take effect and when the tool position changes
to the new shifted location. This manual makes the assumption that the
system is configured to immediately shift the coordinate system by the
geometry and wear amounts, and delay the move that re-positions the tool
to the same coordinate position in the current work coordinate system. See
the documentation prepared by your system installer to determine the
application in a specific system.
Provided your system is configured as described above, the control
activates a tool offset as described below:
The control reads a block that activates or deactivates a tool length
offset. This is a block that contains a T-word for the above
configuration.
The control immediately shifts the work coordinate system the amount
of the tool geometry and tool wear amounts called by the T-word.
Different values can be entered for the offsets for each axis in the offset
table. The tool position display changes reflecting this shift. The
absolute position display does not change.
The offset is interpolated into the next move that generates axis motion
on the offset axis, unless you are in incremental mode. If you are in
incremental mode, the offset is not interpolated into the next move of
the axis.
Example 20.4
Immediate Shift/Delay Move in Incremental and Absolute Modes
Absolute Mode Incremental Mode
G00Z0 Rapid Mode G00Z0 Rapid Mode
G90 Absolute Mode G91 Incremental Mode
T01 Activate tool 1. Program display
changes Z position to -3. T01 Activate tool 1. Program display
changes Z position to -3.
Z1 Axis moves to +1 Z1 Axis moves to -2
If immediate shift, immediate move is selected in AMP, the control
generates its own linear block to create the offset and positions the tool to
the coordinates in the shifted work coordinate system as they were before
the system was shifted. If axis words are present in the block that activates
or deactivates a tool length offset, the control adds this generated move to
the programmed move.
Important: A T-word cannot be programmed in a block that generates a
circular motion (G02 or G03). If you want to change tools during circular
blocks the T-word must be programmed in its own block where no axis
motion takes place.
20.1.2
Activating Tool Length
Offsets