Samson 3730 Series User Manual

3-2 EB 8384-3 EN
Design and principle of operation
lever and to the travel sensor (2) and supplied
toananalogPDcontroller.AnA/Dconverter
(4) transmits the position of the valve to the
microcontroller (5). The PD controller com-
paresthisactualpositiontothe4to20mA
DC control signal (reference variable) after it
hasbeenconvertedbytheA/Dconverter(4).
In case of a set point deviation, the activation
ofthei/pconverter(6)ischangedsothatthe
actuator of the control valve (1) is pressurized
or vented accordingly over the downstream
booster (7). As a result, the closure member
of the valve (e.g. plug) is moved to the posi-
tion determined by the set point.
The supply air is supplied to the booster (7)
andthepressureregulator(8).Anintermedi-
ateowregulator(9)withxedsettingsis
used to purge the positioner and, at the same
time, guarantees trouble-free operation of the
booster. The output signal pressure supplied
by the booster can be limited by software.
The volume restriction Q (10) is used to opti-
mize the positioner.
The extended EXPERTplus diagnostics are in-
tegrated into the positioner. They provide in-
formation on the positioner and generate di-
agnostic and status messages, which allow
faults to be pinpointed quickly.
3.1 Mounting versions
The positioner is suitable for the following
types of attachment using the corresponding
accessories:
− Direct attachment to SAMSON
Type3277Actuator
− Attachment to actuators according to
IEC60534-6:
− AttachmentaccordingtoVDI/
VDE3847-1/-2:
− AttachmenttoType3510Micro-ow
Valve
− Attachment to rotary actuators according
toVDI/VDE3845:
3.2 Additional equipment
Solenoid valve
If the operating voltage for the solenoid
valve (12) fails, the signal pressure for the
booster is vented to the atmosphere. As a re-
sult, the actuator is vented and the valve
moves to its fail-safe position.
The manual set point is automatically reset to
0% after the solenoid valve is activated.
A different manual set point must be entered
again (Code 1).
Position transmitter
The position transmitter (13) is a two-wire
transmitter and issues the travel sensor signal
asa4to20mAsignalprocessedbythemi-
crocontroller.
Since this signal is issued independent of the
positioner's input signal (minimum current
3.8mA),themomentarytravel/angleofro-
tation is controlled in real-time. Additionally,
the position transmitter allows positioner
faults to be indicated over a signal current of
<2.4mAor>21.6mA.
NOTICE
!

Samson 3730 Series Specifications

General

Brand	Samson
Model	3730 Series
Category	Valve Positioners
Language	English