Siemens SINUMERIK 840D - Page 167

5
04.00 Special Motion Commands
5.4 Pol
y
nomial inter
p
olation
,
POLY
5
840D
NCU 571
840D
NCU 572
NCU 573
810D 840Di

Siemens AG 2000. All rights reserved
SINUMERIK 840D/840Di/810D/FM-NC Programming Guide Advanced (PGA)
−
04.00 Edition
5-167
Special case denominator polynomial
Command
PO[]=(...)
can be used to program a
common denominator polynomial for the geometry
axes (without specification of axes names), i.e. the
motion of the geometry axes is then interpolated as
the quotient of two polynomials.
With this programming option, it is possible to
represent forms such as conics (circle, ellipse,
parabola, hyperbola) exactly.
Example
POLY G90 X10 Y0 F100
Geometry axes traverse linearly to
position X10, Y0
PO[X]=(0,–10) PO[Y]=(10) PO[]=(2,1)
Geometry axes traverse along quadrant to
X0, Y10
The constant coefficient (a
0
) of the denominator
polynomial is always assumed to be 1, the specified
end point is not dependent on G90/G91.
The result obtained from the above example is as
follows:
X(p)=10(1–p
2
)/(1+p
2
) and Y(p)=20p/(1+p
2
)
where 0<=p<=1
As a result of the programmed start points, end
points, coefficient a
2
and PL=1, the intermediate
values are as follows:
Numerator (X)=10+0*p–10p
2
Numerator (Y)=0+20*p+0*p
2
Denominator = 1+2*p+1*p
2
X
10
Y