Siemens SINUMERIK 840Di sl Programming Manual page 351

To do this, the tool must be selected again after the plane has been changed.
Turning:
Using NORM and KONT you can determine the tool path for activation/deactivation of
compensation mode (see chapter "Contour approach and retraction", NORM, KONT, G450,
G451).
Caution
Activation/deactivation of tool radius compensation
A travel command must be programmed with G0 or G1 in an NC block with G40, G41 or
G42. This travel command must specify at least one axis in the selected working plane.
If you only specify one axis on activation, the last position on the second axis is added
automatically and traversed with both axes.
The two axes must be active as GEOAX in the channel. This can be achieved by
programming them with GEOAX.
Fundamentals
Programming Manual, 11/2006, 6FC5398-1BP10-2BA0
8.8 Tool radius compensation (G40, G41, G42)
Tool offsets
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