Siemens SINUMERIK 840DE Programming Manual page 325

Tool length compensation
The wear parameter assigned to the diameter axis on tool selection can be defined as the
diameter value (MD). This assignment is not automatically altered when the plane is
subsequently changed. 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.
Intersection
Select intersection with SD 42496: CUTCOM_CLSD_CONT
FALSE:
If two intersections appear on the inside when offsetting an (virtually) closed contour, which
consists of two circle blocks following on from one another, or from one circle block and one
linear block, the intersection positioned closest to the end of block on the first partial contour
is selected, in accordance with standard procedure.
Fundamentals
Programming Manual, 10.2004 Edition, 6FC5 298-7AB00-0BP1
8.8 Tool radius compensation (G40, G41, G42)
Tool offsets
8-29