Samson TROVIS 3730-1 Notice De Montage Et De Mise En Service page 153

13 Description of Equipment or Protective System:
Type 3725
General - The type 3725 electropneumatic positioner is a single-acting positioner for attachment to
pneumatic linear and rotary valves. It is a self-calibrating device with automatic adaptation to valve and
actuator. The positioner is mounted on pneumatic control valves and is used to assign the valve position
(controlled variable x) to the control signal (reference variable w). The positioner compares the electric
control signal of a control system to the travel or rotational angle of the control valve and issues a signal
pressure (output variable y) for the pneumatic actuator.
The positioner consists of a magneto resistive sensor (2), an analog i/p converter (6) with a downstream
booster (7) and the electronics unit with microcontroller (4). The travel or opening angle is measured by the
pick-up lever connected to the sensor (2) installed in the positioner and the downstream electronics. When
a system deviation occurs, the actuator is either vented or filled with air. If necessary, the signal pressure
change can be slowed down by a volume restriction as necessary. The i/p module (6) is supplied with a
constant upstream pressure by the pressure
regulator (8) to make it independent of the supply air pressure.
Construction - The Type 3725 electropneumatic positioner mainly consists of the electronics part. The
parts are assembled in an enclosure made of aluminium die cast or stainless-steel die cast. The enclosure
has a cover with a polymeric inspection window. As an alternative to the polymeric material, the window
can be made from aluminium. The enclosure has an ingress protection rating of IP66
See Annex for model code, thermal and electrical values.
TROVIS 3730-1
General – The TROVIS 3730-1 Positioner is a single acting positioner for attachment to pneumatic control
valves. The positioner mainly consists of a non-contact travel sensor system, an i/p converter and the
electronics with the microcontroller. The valve position is transmitted either as an angle of rotation or a
travel to the pick-up lever, from there to the travel sensor and forwarded to the microcontroller. The PID
algorithm in the microcontroller compares the valve position measured by the travel sensor to the 4 to 20
mA DC control signal issued by the control system after it has been converted by the AD converter. In case
of a set point deviation, the i/p converter causes the actuator to be either vented or filled with air. As a
result, the closure member of the valve is moved to the position determined by the reference variable. The
pneumatic module is supplied with supply air and the flow rate of the module's output can be restricted by
software
Construction - The Type TROVIS 3730-1 HART° Positioner mainly consists of the electronics part. The
parts are assembled in an enclosure made of aluminium die cast or stainless-steel die cast. The enclosure
has a cover with a polymeric inspection window. As an alternative to the polymeric material, the window
can be made from aluminium. The enclosure has an ingress protection rating of IP66
See Annex for model code, thermal and electrical values.
TROVIS 3730-3
General - The Type TROVIS 3730-3 HART® Positioner is a single acting positioner for attachment to
pneumatic control valves. The positioner ensures a predetermined assignment of the valve position
(controlled variable x) to the input signal (reference variable w). It compares the input signal received from
a control system to the travel or rotational angle of the control valve and issues a corresponding output
signal pressure (output variable y) for the pneumatic actuator.
Construction - The Type TROVIS 3730-3 HART° Positioner mainly consists of the electronics part and
one pneumatic module. The parts are assembled in an enclosure made of aluminium die cast or stainless-
THIS CERTIFICATE MAY ONLY BE REPRODUCED IN ITS ENTIRETY AND WITHOUT CHANGE
FM Approvals Ltd. Voyager Place, Maidenhead, Berkshire, SL6 2PJ. United Kingdom
T: +44 (0) 1753 750 000 F: +44 (0) 1753 868 700 E-mail:
F UKEX 020 (Jan/21)
EB 8484-1 FR
to UK-Type Examination Certificate No. FM21UKEX0202X
SCHEDULE
atex@fmapprovals.com www.fmapprovals.com
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