Siemens SIPART DR21, Manual

Page: 80 / 242

3 Functional description of the structure switches
3.4 Controller types (S1, S42 to S45)
Manual
80
SIPART DR21
C73000-B7476-C143-08
1)
constant gas/air-ratio
2)
gas/air-ratio with additional excess air
% mA
Gas
m
3
/h
V=1,33
λ
=0.75
0 2000 4000 6000 8000 10000 12000 m
3
/h air
Q
L
V=1
λ
=1
V=0.8
λ
=1.25
1)
V=1, c<0
2)
X2
4 6 8 10 12 14 16 18 20 mA
X2
0 10 20 30 40 50 60 70 80 90 100 %
22
20
18
16
14
12
10
8
6
4
120
110
100
90
80
70
60
50
40
30
20
10
0
3500
3000
2500
2000
1500
1000
500
X
1
X
1
Q
G
0
Figure 3-15 Display of gas-/air ratio in controlled status
3.4.6 Control unit/process display (S1 = 4)
The following functions are possible in this configuration:
Process display and control unit. The configuration is identical for both applications. The input
wiring for both is illustrated in figure 3-16, page 82.
D
Process display, two-channel analog display with parallel,
switchable digital display (S85 = 0/1 and S42 = 1)
see figure 3-16, page 82
The process variables are assigned to the green analog display by w
EA
and to the red ana-
log display by x2.
The display range of the analog display is 0 to 100 %. The four-digit digital x/w-display is
connected in parallel to the analog displayd by the Shift key (6) to the positions I and II one
after another.
The display range of the digital display is set for both display positions together with the
parameters dA, dE, dP in the oFPA configuring mode. The linearizer (S21) which can be as-
signed to the analog input then acts on both the analog- and the digital display. If this is not
desirable, the linearizer can also be assigned to x1 by S21 = 5 and connect the same analog