# Fanuc Series 15i/150i-MA (Programming) Operators Manual

14.COMPENSATION FUNCTION PROGRAMMING B-63324EN/03
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- Tool holder offset
The machine-specific length from the rotation center of the tool
rotation axes (A- and B-axes, A- and C-axes, and B- and C-axes) to the
tool mounting position is referred to as the tool holder offset. Unlike a
tool length offset value, a tool holder offset value is set in parameter No.
7648. When tool axis direction tool length compensation is applied,
the sum of the tool holder offset and tool length offset is handled as a
tool length for compensation calculation.
Tool holder offset
Tool length offset
Rotation center
Tool
length
Fig.14.12 (b) Tool Holder Offset
- Parameter-based rotation angle specification
A tool compensation vector is found from the coordinates on the
rotation axes for controlling the tool axis direction. However, the
configuration of some machines is such that the tool axis is inclined
using a fixed attachment. In such a case, the rotation angles of the
rotation axes can be set using parameters.
Set bit 1 (RAP) of parameter No. 1014 to 1, and set the coordinates in
parameter No. 7516.
- Rotation axis origin compensation
This function compensates for a slight shift of the rotation axis origin
caused, for example, by thermal displacement. Specify a compensation
value in parameter No. 7518.
When the tool axis is on the Z-axis, and the rotation axes are the B-axis
and C-axis, a compensation vector is calculated as follows :
Xp = Lc * sin(B-Bz) * cos(C-Cz)
Yp = Lc * sin(B-Bz) * sin(C-Cz)
Zp = Lc * cos(B-Bz)
Xp,Yp,Zp : Compensation pulse on each axis after origin shift
compensation
Lc : Offset value
B,C : Machine position on B-axis and C-axis
Bz,Cz : Origin compensation value on B-axis and C-axis