Siemens sinumerik 840d Programming Manual page 328

Path Traversing Behavior
9
9.5 Feed characteristic, FNORM, FLIN, FCUB, FPO
840D 840D
NCU 571 NCU 572
NCU 573
The programmed feed characteristic is always
absolute regardless of G90 or G91.
Additional notes
Compressor
With an active compressor COMPON the following
applies when several blocks are joined to form a
spline segment:
FNORM:
The F word of the last block in the group applies to the
spline segment.
FLIN:
The F word of the last block in the group applies to the
spline segment.
The programmed F value applies until the end of the
segment and is then approached linearly.
FCUB:
The generated feed spline deviates from the
programmed end points by an amount not exceeding the
value set in machine data $MC_COMPESS_VELO_TOL.
F=FPO(...,...,...)
These blocks are not compressed.
Feed optimization on curved path sections
Feed polynomial F-FPO and feed spline FCUB
should always be traversed at constant cutting rate
CFC, thereby allowing a jerk-free setpoint feed
profile to be generated. This enables creation of a
continuous acceleration setpoint feed profile.
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840Di
SINUMERIK 840D/840Di/810D/FM-NC Programming Guide Advanced (PGA) – 04.00 Edition
08.97
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