Siemens SINUMERIK 840D sl Programming Manual page 236

Motion commands
9.8 Involute interpolation (INVCW, INVCCW)
Example 2: Counterclockwise involute with indirect programming of the end point through
specification of an opening angle
Program code
N10 G1 X10 Y0 F5000
N15 G17
N20 INVCCW CR=5 I-10 J0 AR=360
...
References
For more information about machine data and supplementary conditions that are relevant to
involute interpolation, see:
Function Manual, Basic Functions; Various NC/PLC interface signals and functions (A2),
Chapter: "Settings for involute interpolation"
236
Comment
; Approach of the starting position.
; Selection of the X/Y plane as working
plane.
; Counterclockwise involute and away from
the basic circle (as positive angle
specification) with one full revolution
(360 degrees).
Programming Manual, 09/2011, 6FC5398-1BP40-2BA0
Fundamentals