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Siemens Building Technologies
Electronic Air / Fuel Ratio Control System
CC1P7873.1en
HVAC Products
8 Block circuit diagram
15.10.2002
8
Block circuit diagram
Q1
L
N
S1
RVW26
Fuel1
Fuel2
S2
QUIT
78731a03/0601
4)
3)
2)
Q4
Y5
Y6
F1
F2
Y10
Y20
Q2
Q3
Q5
6)
5)
1)
17)
Test
AZW20.20
14)
15)
TxD
U10
M
EEPROM
(RZD20)
12)
B4
B3
B2
U3
11)
10)
TxD
D
9)
R1
R3
R3
R2
R2
R2
R2
RxD
SA5
SA6
M
icr
o
p
ro
ce
s
s
o
r
A
temp
D
A
X3
X1
R4
G
Y8
16)
SA5
SA6
SA7
(AUX1(1))
18)
H
U1
X2
Y3
Y4
Watch
dog
M
M
FU
(AUX1(2))
(AUX2)
Detect Terminal
SA7
M
%
7)
1
2
PROM
8)
P
P
P
RxD
GND
Fig. 17
Block circuit diagram
1)
Mains transformer with built-in thermal
11) Inputs from feedback potentiometers
cutout
(inputs «B2» and «B3» are switched
2)
Fuse «S1» for outputs
internally, according to the type of fuel
«Y3...Y4» and «Q1»
currently burnt)
3)
Acknowledge relay with contact «Q1»
12) Data memory as an
4)
Readiness relay with readiness contact
exchangeable plug-in module
«Q4...Q5», «H» and fuse «S2»
14) Socket for the
5)
Mains voltage inputs with optocoupler
handheld terminal AZW20.20
6)
Control outputs
15) Interface output for RVW25.000B27
7)
Display on the front of the unit
16) Actuators «SA5...SA7» with
8)
Program memory
feedback potentiometer
9)
Signal output «X1» (burner output
17) Signal input «U1» DC 0...10 V for
DC 0...10 V) with D / A converter
controlling the burner output
10)
Signal input «X2» (correcting variable
18) Signal input «U3» DC 0...10 V for the
DC 0...10 V, e.g.
O
2
trim control)
required speed of the speed
controller of the RVW25...
Legend
