Siemens SINUMERIK 840D sl Programming Manual page 167

The control requires the specification of the working plane for the calculation of the direction
of rotation (see circular interpolation G2/G3).
Machining on inclined planes
Rotate the coordinate system with ROT (see Section "Coordinate system offset") to position
the coordinate axes on the inclined surface. The working planes rotate accordingly.
Tool length compensation on inclined planes
As a general rule, the tool length compensation always refers to the fixed, non-rotated
working plane.
Milling:
Note
The tool length components can be calculated according to the rotated working planes with
the functions for "Tool length compensation for orientable tools".
The compensation plane is selected with CUT2D, CUT2DF. For further information on this
and for the description of the available calculation methods,see Chapter "Tool radius
compensation [Page 277]".
The control provides convenient coordinate transformation functions for the spatial definition
of the working plane. Please see Chapter "Coordinate transformations (frames) [Page 337]"
for more information.
Fundamentals
Programming Manual, 09/2011, 6FC5398-1BP40-2BA0
8.2 Selection of the working plane (G17/G18/G19)
Geometry settings
167