Siemens SINUMERIK 840D sl Programming Manual page 238

Special motion commands
4.2 Spline interpolation (ASPLINE, BSPLINE, CSPLINE, BAUTO, BNAT, BTAN, EAUTO, ENAT, ETAN, PW,
SD, PL)
Spline type
C spline
238
Properties and use
Features:
The passes precisely through the specified intermediate points along the

curve.
The curve characteristic is tangential with continuous curvature.

Frequently generates undesirable oscillations, especially at positions where

the gradient changes significantly.
The area of influence of changes to the intermediate points is global. This

means that if an intermediate point is changed then this influences the
complete curved characteristic.
Application:
The C spline can be well used if the intermediate points lie on a curve that can
be analytically calculated defined (circle, parabola, hyperbola).
Programming Manual, 03/2013, 6FC5398-2BP40-3BA1
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