Samson 3730-3 - Design and Principle of Operation; Block Diagram

EB 8384-3 EN 17
Design and principle of operation
3 Design and principle of oper-
ation
Î RefertoFig.1
The electropneumatic positioner is mounted
on pneumatic control valves and is used to
assign the valve position (controlled vari
-
ablex)tothecontrolsignal(setpointw).The
electric signal from a controlling system is
compared to the travel or the rotational angle
of the control valve and a signal pressure
(output variable y) is produced for the actua
-
tor.
The positioner consists of a travel sensor sys
-
tem (2) proportional to resistance, an analog
i/pconverterwithadownstreamaircapacity
booster (7) and the electronics with microcon
-
troller (5).
Thepositioneristtedwiththreebinarycon
-
tacts as standard: A fault alarm output indi-
cates a fault to the control room and two con-
gurablesoftwarelimitswitchesareusedto
indicate the end positions of the valve.
1 Control valve
2 Travel sensor
3 PD controller
4 A/Dconverter
5 Microcontroller
6 i/pconverter
7 Air capacity booster
8 Pressure regulator
9 Flow regulator
10 Volumerestriction
11* Inductive limit switch
12* Solenoid valve
13* Analog position transmitter
14 Software limit switch, alarm
1/2
15 Fault alarm output, alarm 3
16 Display
17* Actuation of solenoid valve
18* Electrical insulation
19 D/Aconverter
20 Communication interface
21 HART
®
connection
22 Binary input BE*
* Option
w
x
Q
%
S
mm
GG
PD
Serial
Interface
16
13
22
15
A2
A3
BE
A1
11
2
4
21
FSK
20
19
5
3
12
6
7
8
10
1
14
14
w
x
y
24 V DC
9
17
18
Fig.1: Block diagram