Polynomial Evaluation (Synfct) - Siemens SINUMERIK 828D Function Manual

2.7.3

Polynomial evaluation (SYNFCT)

Application
A variable that is evaluated via a polynomial can be read with the SYNFCT function in the
main run and the result written to another variable. Application examples:
● Feedrate as a function of drive load
● Position as a function of a sensor signal
● Laser power as a function of path velocity
Syntax
SYNFCT(<Poly_No>,<SysVar_Out>,<SysVar_In>)
Meaning
Parameter
<Poly_No>
<SysVar_Out>
<SysVar_In>
For information on
(Page 42)"
Example: Additive override of the path feedrate
An override value is added to the programmed feedrate (F word):
F
active
<SysVar_Out>
$AC_VC
$AA_VC[axis]
Input value is the actual current value $AA_CURR of the X axis.
The operating point is set to 5 A.
The feedrate may be altered by ±100 mm/min whereby the axial current deviation may be ±1
A.
Synchronized actions
Function Manual, 07/2012, 6FC5397-5BP40-3BA0
Meaning
: Number of the polynomial defined with
f(x) = a
: System variable, output:
<SysVar_Out> =
: System variable, input:
x =
, see Section "Polynomial coefficients, parameters ($AC_FCT ...)
FCTDEF
= F + F
programmed AC
Meaning
Additive path feedrate override
Additive axial feedrate override
+ a x + a x + a x
2 3
0 1* 2* 3*
f(x)
<SysVar_In>
Detailed description
2.7 Actions in synchronized actions
:
FCTDEF
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