Siemens Sinumerik 840D sl Programming Manual page 280

Tool radius compensation
11.4 Smooth approach and retraction
Figure 11-5
Collision monitoring CDON, CDOF
If CDOF is active (see section Collision monitoring, CDON, CDOF), the search is aborted when
an intersection is found, i.e., the system does not check whether further intersections with
previous blocks exist.
If CDON is active, the search continues for further intersections after the first intersection is
found.
An intersection point, which is found in this way, is the new end point of a preceding block and
the start point of the deactivation block. The inserted circle is used exclusively to calculate the
intersection and does not produce a traversing movement.
Note
If no intersection is found, alarm 10751 (collision danger) is output.
G462
If no intersection is possible between the last TRC block and a preceding block, a straight line
is inserted, on retraction with G462 (initial setting), at the end point of the last block with tool
radius compensation (the block is extended by its end tangent).
The search for the intersection is then identical to the procedure for G461.
Retraction behavior with G462 (see example)
With G462, the corner generated by N10 and N20 in the example program is not machined to
the full extent actually possible with the tool used. However, this behavior may be necessary
if the part contour (as distinct from the programmed contour), to the left of N20 in the example,
is not permitted to be violated even with y values greater than 10 mm.
Corner behavior with KONT
280
Retraction behavior with G461
Programming Manual, 01/2015, 6FC5398-1BP40-5BA2
Fundamentals