Siemens SINUMERIK 840D sl Programming Manual page 265

4.2 Spline interpolation (ASPLINE, BSPLINE, CSPLINE, BAUTO, BNAT, BTAN, EAUTO, ENAT, ETAN, PW, SD, PL)
Spline degree (only B spline):
SD
Distance between nodes (only B spline):
PL
<value>
Transitional behavior at the start of the spline curve (only A or C spline):
BAUTO
BNAT
BTAN
Transitional behavior at the end of the spline curve (only A or C spline):
EAUTO
ENAT
ETAN
Job Planning
Programming Manual, 06/2009, 6FC5398-2BP20-0BA0
A third degree polygon is used as standard, However, a second
degree polygon can also be used by programming SD=2.
The distances between nodes are suitably calculated internally.
The control can also machine pre-defined node clearances that
are specified in the so-called parameter-interval-length using the
PL command.
Parameter interval length
Range of values: As for path dimension
No specifications for the transitional behavior. The start is
determined by the position of the first point.
Zero curvature
Tangential transition to the previous block (delete position)
No specifications for the transitional behavior. The end is
determined by the position of the last point.
Zero curvature
Tangential transition to the previous block (delete position)
Special motion commands
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