YASKAWA SIEMENS CNC Series, Maintenance Manual, Serviceman Handbook

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Drive set-up procedure
14.4.3 Spline interpolation
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14.4.3 Spline interpolation
„ General spline interpolation
Set the following machine data as the conditions for general spline interpolation to be
enabled within CNC.
• MD28530 PATH_VELO_SEGMENTS
Meaning: Number of polynomial spline per block
Setting this value allows the feed speed to be controlled to have better
waveform.
Standard setting value: 5
• MD28540 ARCLENGTH_SEGMENTS
Meaning: Number of polynomial spline within a single spline curve
Setting this value allows the deviation of feed speed to decrease on the
curve sections.
Standard setting value: 10
„ Spline interpolation with NC program command
This allows the curve interpolation for linear blocks with the spline interpolation.
There are 3 types of spline curve for interpolation:
• A spline (Akima spline): Spline interpolation which always goes through the instructed
points. The radius of curvature does not vary continuously.
• B spline (B-spline): Smooth spline interpolation which goes by the instructed points.
• C spline (Cubic spline): Spline interpolation which always goes through the instructed
points and whose radius of curvature varies continuously on the instructed points.
P1
P2
P3
P5
P4
P6
P7
A spline
B spline
C spline