Additional Equipment - Samson 3730-2 Mounting And Operating Instructions

troller compares this actual position to the 4
to 20 mA DC control signal (set point) after it
has been converted by the A/D converter
(4). In case of a set point deviation, the acti-
vation 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 clo-
sure member of the valve (e.g. plug) is
moved to the position determined by the set
point.
The supply air is supplied to the booster (7)
and the pressure regulator (8). An intermedi-
ate flow regulator (9) with fixed 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
integrated into the positioner. They provide
information on the positioner and generate
diagnostic and status messages, which allow
faults to be pinpointed quickly.
The positioner is suitable for the following
types of attachment using the corresponding
accessories:
− Direct attachment to SAMSON
Type 3277 Actuators
− Attachment to actuators according to
IEC 60534-6 (NAMUR)
− Attachment according to VDI/VDE 3847
− Attachment to Type 3510 Micro-flow
Valve
EB 8384-2 EN
Design and principle of operation
− Attachment to rotary actuators according
to VDI/VDE 3845

3.1 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.
NOTICE
!
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
microcontroller.
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.
Inductive limit switch
In this version, the rotary shaft of the posi-
tioner carries an adjustable tag which actu-
ates the built-in proximity switch. The option-
al inductive switch (11) is connected to A1,
while the remaining software limit switch is
connected to A2.
11