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

B-63324EN/03 PROGRAMMING 9.SPINDLE SPEED FUNCTION (S FUNCTION)
- 227 -
- Setting the workpiece coordinate system for constant surface speed control
To execute the constant surface speed control, it is necessary to set the
work coordinate system , and so the coordinate value at the center of
the rotary axis, for example, Z axis, (axis to which the constant surface
speed control applies) becomes zero.
X
Z
0
Fig.9.2 (b) Example of the workpiece coordinate system for
constant surface speed control
- Value of S specified in G96 mode
The S value specified in G96 mode is stored even after G97 mode has
turned
G96 S50 : 50 m/min or 50 feet/min
G97 S1000 : 1000 min
-1
G96 X3000 : 50 m/min or 50 feet/min
- Speed when G97 mode is resumed
If S (min
-1
) is not specified in a G97 block when the mode switches
from G96 mode to G97 mode, the last speed to be used at the end of
G96 mode is used as S in G97 mode.
N10 G97 S800 : 800 min
-1
N20 G96 S100 : 100 m/min or 100 feet/min
N30 G97 : X min
-1
X represents the speed used in the previous mode. This means that the
spindle speed is maintained upon a transition from G96 mode to G97
mode.
If S (min
-1
) is not specified in a G96 block when the mode initially
switches from G97 mode to G96 mode, S = 0 m/min is used.
- Constant surface speed control in rapid traverse (G00)
In rapid traverse, the surface speed is constantly being calculated as the
tool position changes. When bit 6 (RSC) of parameter No. 5602 is set
to 1, however, the surface speed is calculated from the position of the
end point of the block
- Constant surface speed control when machine lock is used
With machine lock, the constant surface speed is calculated according
to a change of the coordinate values of the axis to which the constant
surface speed control is applied, even if the machine tool does not
move.