Description; Function; Structure; Overview Of Structure - Siemens SIPART PS2 Operating Instructions Manual

Description

3.1

Function

● The electropneumatic positioner and an actuator form a control system. The current position
of the actuator is recorded by a servo potentiometer and the actual value x is fed back. The
setpoint and the actual value are also shown simultaneously on the display.
● The control system provides the setpoint w digitally to the positioner over the bus.
● The positioner works as a predictive five-point positioner, through whose output value ±Δy
the integrated valves can be controlled by pulse length modulation.
● These input signals change pressure in the actuator chamber(s) and displace the actuator
until the control deviation becomes zero.
● Using the three buttons and the display with the enclosure cover removed, operation
(manual mode) and configuration (structuring, initialization, and parameter assignment)
can be performed.
● By default, the basic unit has a binary input (BIN). This binary input can be individually
configured and used, for example, to block the control levels.
● It has a friction clutch and a switchable gear so that the positioner can be used with different
mechanical part-turn and linear actuators.
● In the case of positioners with the "Fail in Place" function, the current position of the actuator
is held if the electric and/or pneumatic auxiliary power fails. Does not function in conjunction
with SIL.
3.2

Structure

3.2.1

Overview of structure

The following sections describe the mechanical and electrical structure, components, and
principle functionality of the positioner.
The positioner is used to move and control pneumatic actuators. The positioner works
electropneumatically, using compressed air as auxiliary power. The positioner is used to
control valves, for example, with:
● Linear actuator
● Part-turn actuator VDI/VDE 3845
Various add-on extensions are available for linear actuators:
● IEC 60534-6-1 (NAMUR)
● Integrated mounting on ARCA, except with flameproof stainless steel enclosure (6DR5..6)
● Integrated mounting on SAMSON, not for Ex d
SIPART PS2 with and without HART
Operating Instructions, 05/2017, A5E00074631-AC
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