Siemens SINUMERIK 840D sl Function Manual page 167

2.3 Continuous-path mode
2.3.1 General
Continuous-path mode
In the continuous-path mode the path velocity is not decelerated for the block change in
order to permit the fulfillment of an exact stop criterion. The objective of this mode is to avoid
rapid deceleration of the path axes at the block-change point so that the axis velocity
remains as constant as possible when the program moves to the next block. To achieve this
objective, the "LookAhead" function is also activated when continuouspath mode is selected.
Continuouspath mode causes the smoothing and tangential shaping of angular block
transitions by local changes in the programmed contour. The extent of the change relative to
the programmed contour can be limited by specifying the overload factor or rounding criteria.
Continuouspath operation causes:
• Contour rounding
• Shorter machining times through elimination of braking and acceleration processes that
• Improved cutting conditions because of the more constant velocity
Continuouspath mode is suitable if:
• A contour must be traversed as quickly as possible (e.g., with rapid traverse).
• The exact contour may deviate from the programmed contour within a specific tolerance
Continuous-path mode is suitable if:
• A contour is to be traversed precisely.
• An absolutely constant velocity is required.
Implicit exact stop
In some cases, an exact stop needs to be generated in continuouspath mode to allow the
execution of subsequent actions. In such situations, the path velocity is reduced to zero.
• If auxiliary functions are output before the traverse motion, the previous block is only
• If auxiliary functions are to be output after the traverse motion, they are output after the
• If an executable block (e.g., starting a positioning axis) contains no travel information for
• If a positioning axis is declared to be the geometry axis, the previous block is terminated
Basic logic functions: Continuouspath Mode, Exact Stop, LookAhead (B1)
Function Manual, 11/2006, 6FC5397-0BP10-2BA0
are required to comply with the exact-stop criterion
for the purpose of obtaining a continuous contour.
terminated when the selected exact-stop criterion is fulfilled.
interpolator end of the block.
the path axes, the previous block is terminated on reaching the selected exact-stop
criterion.
at the interpolator end when the geometry axis is programmed.
Detailed description
2.3 Continuous -path mode
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