Siemens SINUMERIK 840D sl Function Manual page 209

Program code
N10012 X11.635 Y149.679 Z5.010
N10013 X12.032 Y149.679 Z5.031
M30
Note
When switching between the standard Look Ahead functionality and the "Free-form surface
mode: Extension function" or vice versa, continuous-path mode is interrupted by an interpolator
stop.
Supplementary conditions
Automatic function switchover
Use of the following functions results in an automatic switchover to standard Look Ahead
functionality:
● Thread cutting/tapping (G33, G34, G35, G331, G332, G63)
● Path master-value coupling
● Punching, nibbling
● Cartesian PTP travel
The "Free-form surface mode: Extension function" is then switched on again automatically.
Using the commands of G function group 15 (feed types)
The following feed types are not recommended in conjunction with the "Free-form surface
mode: Extension function".
● Feedrate per revolution (G95, G96, G97, etc.)
● Inverse-time feedrate (G93)
Use of FLIN
The FLIN feedrate profile cannot be used in conjunction with the "Free-form surface mode:
Extension function".
Influence of feedrate overrides
Feedrate overrides (via a machine control panel, $AC_OVR, ...) can extend the traverse time
over standard Look Ahead functionality considerably.
Interaction with rapid traverse motion (G0)
G0 blocks which are interspersed during free-form surface processing do not switch the Look
Ahead functionality over (from the "Free-form surface mode: Extended function" to the
standard Look Ahead functionality or vice versa). This means that even though the standard
dynamic response setting (DYNNORM) is effective with G0, the standard Look Ahead
functionality which is preset for DYNNORM (→ MD20443 $MC_LOOKAH_FFORM[0]) does
not automatically become effective as well. By retaining the Look Ahead functionality which is
currently active, a more homogeneous velocity profile is achieved, particularly since G0 and
polynomial blocks are usually smoothed and connected by rounding.
Basic Functions
Function Manual, 01/2015, 6FC5397-0BP40-5BA2
B1: Continuous-path mode, Exact stop, Look Ahead
Comment
4.3 Continuous-path mode
209