Mounting Versions; Additional Equipment - Samson 3730-3 Mounting And Operating Instructions

Design and principle of operation
The valve position is transmitted as a either
an angle of rotation or travel to the pick-up
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 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 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 (see section 3.6):
18
− Direct attachment to SAMSON
Type 3277 Actuator
Î See section 5.3.
− Attachment to actuators according to
IEC 60534-6:
Î See section 5.4.
− Attachment according to VDI/
VDE 3847-1/-2:
Î See section 5.5 and section 5.6.
− Attachment to Type 3510 Micro-flow
Valve
Î See section 5.7.
− Attachment to rotary actuators accord-
ing to VDI/VDE 3845:
Î See section 5.8.

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.
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
EB 8384-3 EN