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Description
3.2 Structure
The SIL device is certified in order to test partial strokes in applications up to SIL 2. The
result of this so-called partial stroke test is then reported with digital output DO 1 (fail-safe).
Optionally, the result can also be reported through HART communication.
3.2
Structure
3.2.1
Overview of structure
Introduction
The electropneumatic positioner is made up of the following components:
● Enclosure and cover
● Display module with terminals
● Controller module
● Sensors for non-contacting position detection
● Pneumatic block
The valve block is located in the enclosure. Both the pneumatic interface and the mechanical
interface of the SITRANS VP300 are provided by the innovative OPOS. Behind this name
stand the directive VDI/VDE 3847, with additional functionality and greater customer benefit.
The positioner is mounted on the front with only two screws and is ready for operation
without any external piping. If the interface of the actuator does not correspond with the
VDI/VDE 3847 directive, the positioner is mounted using the adapter block of the
corresponding mounting kit. An overview of the mounting kits can be found in the FI 01
catalog.
With the SITRANS VP300, position detection is carried out on a non-contacting basis using a
magnet and sensors in the positioner. The magnet for position detection on a non-contact
basis is in the magnet clamp. In the case of linear actuators, the magnet clamp is attached to
the drive spindle and moves up and down on the back of the positioner. In the case of part-
turn actuators, the magnet clamp is attached to the shaft butt of the drive and turns
underneath the positioner. The valve position is detected by the robust GMR principle, which
identifies the direction of the magnetic field lines. GMR stands for "giant magnetoresistance".
Gauges for displaying pressure can be fastened to the adapter block as an accessory, and
you can connect a safety solenoid valve. A shutdown tap for the compressed air
connections, which is useful when replacing the device without having to shut down the
equipment, can also be connected.
16
SITRANS VP300 with or without HART
Operating Instructions, 03/2011, A5E01258666-03
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