Siemens SINUMERIK 840Di sl Programming Manual page 354

Tool offsets
8.8 Tool radius compensation (G40, G41, G42)
Note
Compensation mode
Compensation mode may only be interrupted by a certain number of consecutive blocks or
M commands, which do not contain any travel commands or positional parameters in the
compensation plane: Standard 3.
Machine manufacturer
The number of consecutive blocks or M commands can be set in machine data 20250 (see
machine manufacturer).
Note
A block with a path distance of zero also counts as an interruption!
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Programming Manual, 11/2006, 6FC5398-1BP10-2BA0
Fundamentals