Samson 3730-2 - Design and Principle of Operation

EB 8384-2 EN 19
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
system (2) proportional to resistance, an
analogi/pconverterwithadownstreamair
capacity booster (7) and the electronics with
microcontroller (5).
Thepositioneristtedwiththreebinary
contacts as standard: A fault alarm output
indicates 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
22 Binary input BE*
* Option
w
x
%
S
mm
GG
PD
Serial
Interface
16
20
13
15
A2
A3
A1
11
2
4
19
5
3
12
6
7
8
1
14
14
w
Q
10
x
y
24V DC
9
17
18
22
BE
Fig.1: Block diagram