
17. MEASUREMENT FUNCTIONS
B–63522EN/02
NC FUNCTION
246
- Setting of work coordinate system shift amount
The work coordinate system shift amount along the Z axis is to be set
as follows. When the tool touches the end face of the workpiece, the
touch detection signal (workpiece coordinate system shift write
signal) is output. This signal is used to set the workpiece coordinate
system shift, calculated by subtracting the tool geometry
compensation value (shift of coordinate system due to tool geometry
compensation) from the current machine coordinate (distance between
the end face of the workpiece and the tip of the measurement tool when
it is at the machine reference position (machine zero point)). In this
case the tool geometry offset amount corresponding to the tool must
be programmed previously.
Machine
coordinate value
of Z axis (Zt)
Work coordinate
system shift amount
along Z axis to be
set (EXOFSz)
Tool geometry offset
amount of Z axis of
corresponding tool
(OFSz)
=
+
By the above procedure the work coordinate system with the work edge
(sensor contact point) being taken as the work coordinate system zero
point of the Z axis (the program zero point) is set when the tool is selected
by the program command (T code).
–EXOFS
Z
OFS
Z
Z
t
OFS
X
+X
+Z
Machine
zero point
EXOFSz : Work coordinate system shift amount to be set
OFSz : Tool geometry offset amount
Zt : Machine coordinate value (Distance to work edge)
Work coordinate system
zero point
(Program zero point)
Measured tool
nose position
at machine ref-
erence position