Siemens SINUMERIK 840D sl Programming Manual page 315

Example 1: Bottleneck detection
As the tool radius selected for the machining of this inside contour is too large, the
"bottleneck" is bypassed.
An alarm is output.
Example 2: Contour path shorter than tool radius
The tool bypasses the workpiece corner on a transition circle, then continues on the
programmed path.
Fundamentals
Programming Manual, 09/2011, 6FC5398-1BP40-2BA0
10.5 Collision monitoring (CDON, CDOF, CDOF2)
Tool radius compensation
315