Samson TROVIS 3730-1 - Design and principle of operation; 3.1 Types of attachment

14 EB 8484-1 EN
Design and principle of operation
3 Design and principle of oper-
ation
Î RefertoFig.1.
TheTROVIS3730-1ElectropneumaticPosi-
tioner is mounted on pneumatic control
valves and used to assign the valve position
(controlled variable x) to the control signal
(set point w). The positioner compares the
electric control signal of a control system to
the travel or opening angle of the control
valve and issues a signal pressure for the
pneumatic actuator.
The positioner mainly consists of a non-con-
tact travel sensor system (2), pneumatics and
the electronics with the microcontroller (4).
The valve position is transmitted either as an
angle of rotation or a travel to the pick-up le-
ver, from there to the travel sensor (2) and
forwarded to the microcontroller (4). The PID
algorithm in the microcontroller compares
the valve position measured by the travel
sensor(2)tothe4to20mADCcontrolsig-
nal issued by the control system after it has
beenconvertedbytheA/Dconverter(3).
In case of a set point deviation, the activa-
tionofthei/pmodule(7)ischangedsothat
the actuator of the control valve (1) is pres-
surized or vented accordingly over the
downstream booster (6). As a result, the clo-
sure member of the valve (e.g. plug) is
moved to the position determined by the set
point.
The positioner is operated by a rotary push-
button (9) for menu navigation on the dis-
play (11).
1 Control valve
2 Travel sensor
3 A/Dconverter
4 Microcontroller
5 Pressure reducer
6 Air capacity booster
7 i/pconverter
8 D/Aconverter
9 Communication interface
10 Rotarypushbutton
11 Display
12
1)
Softwarelimitcontact(PLC/NAMUR)
13
1)
Position transmitter
14
1)
Inductivelimitcontacts(NAMUR)
1)
Optional
I
I
E
E
µC
#
w
1
3
4
8
7
910
y
x
Serial Interface
12
12
13
14
14
6
5
2
Exhaust Supply 9 Output 38
%
mm
%
mm
S
11
Fig.1: Block diagram
3.1 Types of attachment
TheTROVIS3730-1Positionerissuitablefor
the following types of attachment using the
correspondingaccessories(seesection3.5):
− Direct attachment to Type3277 Actua-
tor
The positioner is mounted on the yoke.
The signal pressure is connected to the
actuator over a connection block: inter-
nally over a hole in the valve yoke for
"actuator stem extends" fail-safe action
and through an external signal pressure
line for "actuator stem retracts" fail-safe
action.
Î Seesection5.3.
− Attachment to actuators according to
IEC60534-6:
The positioner is mounted to the control
valve using a NAMUR bracket.
Î Seesection5.4.
− Attachment according to VDI/
VDE3847-1/-2:
AttachmentaccordingtoVDI/
VDE3847-1/-2usingthecorresponding
accessories allows the positioner to be
replaced quickly while the process is run-
ning.
Î Seesection5.5andsection5.6.
− Attachment to Type3510 Micro-ow
Valve
The positioner is attached to the valve
yoke using a bracket.
Î Seesection5.7.