Siemens SINUMERIK 840DE Programming Manual page 129

Indication of working plane
The control needs the working plane parameter (G17 to G19) in order to calculate the
direction of rotation for the circle – G2 is clockwise or G3 is counterclockwise.
It is advisable to specify the working plane generally.
Exception:
You can also machine circles outside the selected working plane (not with arc angle and
helix parameters). In this case, the axis addresses that you specify as an end point
determine the circle plane.
Programmed feedrate
You can use FGROUP to specify, which axes are to be traversed with a programmed
feedrate. For more information please refer to the Path behavior section.
Fundamentals
Programming Manual, 10.2004 Edition, 6FC5 298-7AB00-0BP1
4.6 Circular interpolation with center point and end point (G2/G3, I=, J=, K=AC...)
Programming Motion Commands
4-23