S1 = 4: Commanded Ratio Controller - Siemens SIPART DR22 Manual

1 Technical Description
1.5 Functional description of the structure switches
1.5.4 Controller types (S1, S49 to S53)
1.5.4.6 S1 = 4:
wvi
w
V
ES
SES
tS
w
SL
Δw
w
w
V
E
FE3
w
V
EA
FE2
x2
FE1
x1
FE4
z
Figure 1-32 Principle representation S1 = 4
In a ratio control the commanding process variable x2 is evaluated with the adjustable ratio fac-
tor and a basic value c5 added if necessary and forms the setpoint w for the following controlled
process variable x1:
w = v ⋅ x2 + c5
With xd = w - x1, xd = v ⋅ x2 + c5 -- x1 is given
In the controlled status (xd = 0), the following is given v =
x1
and at c5 = 0 behaves according to the set ratio factor v.
x2
A typical application are combustion rules where a fuel volume x1 beongs to every air volume
x2 to guarantee optimum combustion.
The ratio factor range v = vA to vE is determined with the parameters vA and vE in the structur-
ing mode oFPA in the range from 0.0 to 9.999 (factory setting vA = 0, vE = 1). In addition a ba-
sic value c5 (parameterization mode onPA) can be connected in the range from -1.999 to 9.999
(factory setting = 0.0).
The standardized nominal ratio wv (wvi or wv
factor range.
v = wv (vE -- vA) + vA
With w = v ⋅ x2 + c5 , w = wv [(vE -- vA) + vA] x2 + c5 is given.
64
commanded ratio controller
0000
wv w
wv
T
s
w=v⋅x2+c5
Int⋅CB
v = vA to vE
x2
v = wv·(vE - vA)
SL
+vA
x1 - c5
v =
ist
x2
0000
xv x
x w
W
+
P I D
--
X
x1 -- c5
x2
) in the range from 0 to 1 is converted to the ratio
E
Manual
000
y
H
ya+c6⋅z
y
a
i.e. in the controlled status
SIPART DR22 6DR2210
C79000-G7476-C154-03
y