Polynomial Definition (Fctdef) - Siemens SINUMERIK 840D sl Programming Manual

10.4.6

Polynomial definition (FCTDEF)

Function
FCTDEF can be used to define 3rd order polynomials in the form y=a
polynomials are used by the online tool offset (FTOC) and the evaluation function
(SYNFCT).
Syntax
FCTDEF(Polynomial No.,LLIMIT,ULIMIT,a
Significance
Polynomial_No.
LLIMIT
ULIMIT
a0, a1, a2, a3
These values can also be accessed via system variables
$AC_FCTLL[n]
$AC_FCTUL[n]
$AC_FCT0[n]
$AC_FCT1[n]
$AC_FCT2[n]
$AC_FCT3[n]
Note
Writing system variables
• The system variables can be written from the part program or from a synchronized action.
• The $AC_FCTLL[n], $AC_FCTUL[n], $AC_FCT0[n] to $AC_FCTn[n] system
When writing form synchronized actions, the polynomial coefficients and function value limits
are active immediately.
Job Planning
Programming Manual, 06/2009, 6FC5398-2BP20-0BA0
When writing from part programs, program STOPRE to ensure that writing is block
synchronized.
variables can be changed from synchronized actions
Motion synchronous actions
10.4 Actions in synchronized actions
0
,a ,a ,a )
0 1 2 3
Number of the 3rd order polynomial
Lower limit for function value
Upper limit for function value
Polynomial coefficient
Lower limit for function value
Upper limit for function value
a
0
a
1
a
2
a
3
+a x+a x +a x . These
2 3
1 2 3
671