Siemens SINUMERIK 840Di sl Programming Manual page 142

Motion commands
4.8 Circular interpolation with arc angle and center point (G2/G3, AR=)
Example of milling
Programming a circle with opening angle and center point or end point
N10 G0 X67.5 Y80.211
N20 G3 X17.203 Y38.029 AR=140.134 F500
or
N20 G3 I–17.5 J–30.211 AR=140.134 F500
Example of turning
Programming a circle with opening angle and center point or end point
N125 G1 X40 Z-25 F0.2
N130 G3 X70 Z-75 AR=135.944
142
X
3
25 25
54.25 54.25
95 95
Z
Programming Manual, 11/2006, 6FC5398-1BP10-2BA0
Fundamentals