Siemens Sinumerik 840D sl Programming Manual page 527

CTAB with periodic curve tables
If the specified <master value> is outside the definition range, the master value is
evaluated modulo of the definition range and the corresponding following value is output:
Approximate value for CTABINV
The CTABINV command, therefore, requires an approximate value for the expected master
value. CTABINV returns the master value that is closest to the approximate value. The
approximate value can be, for example, the master value from the previous interpolation
cycle.
Incline of the curve table function
The output of the incline (<gradient>) makes it possible to calculate the velocity of the
leading or following axis at the corresponding position.
Specification of the leading or following axis
The optional specification of the leading and/or following axis is important if the leading and
following axes are configured in different length units.
CTABSSV, CTABSEV
The CTABSSV and CTABSEV commands are not suitable to query programmed segments in
the following cases:
• Circles or involutes are programmed.
• Chamfer or rounding with CHF/ RND is active
• Smoothing with G643 is active
• NC block compression with COMPON/COMPCURV/COMPCAD is active
Job planning
Programming Manual, 02/2011, 6FC5398-2BP40-1BA0
Axis couplings
9.2 Curve tables (CTAB)
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