cat fi-01 ch06 2008 ...

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© Siemens AG 2007
Electropneumatic
positioners
SIPART PS2
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Product overview
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Technical description
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Technical Specifications
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- all versions
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-SIPART PS2
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-SIPART PS2 PA
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-SIPART PS2 FF
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- Option modules
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Ordering data
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- SIPART PS2, PS2 PA, PS2 FF
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- SIPART PS2 EEx-d, PS2 EEx-d PA,
PS2 EEx-d FF
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Dimensionsal drawings
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Schematics
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Mounting kits
Software
Sec. 9
SIMATIC PDM, for parameterize
HART and PROFIBUS PA devices
You can download all instructions, cata-
logs and certificates for SIPART PS2 free
of charge at the following Internet
address:
www.siemens.com/sipartps2
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SIPART PS2
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-Accessories
   © Siemens AG 2007
Electropneumatic positioners
Product overview
â– 
Overview
Application
Device description
Catalog
page
Software for
parameterization
Electropneumatic positioners SIPART PS2
Position control
Pneumatic linear or part-
turn actuators, also for
intrinsically-safe opera-
tion
SIPART PS2
Universal device for positioning pneumatic actuators
• Connection: 4 to 20 mA
• HART, PROFIBUS PA or Foundation Fieldbus
• Local manual operation
• Binary inputs and outputs
• Diagnosis functions
• Blocking function
• Automatic startup
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SIMATIC PDM
As above, but in flame-
proof casing for explo-
sion-proof application
SIPART PS2
As above, but in flameproof aluminium
casing
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SIMATIC PDM
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Siemens FI 01 · 2008
© Siemens AG 2007
Electropneumatic positioners
SIPART PS2
Technical description
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Overview
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Benefits
SIPART PS2 positioners offer decisive advantages:
• Simple installation and automatic commissioning (self-adjust-
ment of zero and span)
• Simple operation with
- Local operation and configuration of the device using three
input keys and a user-friendly two-line LCD
- Programming through SIMATIC PDM
• Very high-quality control thanks to an online adaptation proce-
dure
• Negligible air consumption in stationary operation
• "Tight shut-off" function (ensures maximum positioning pres-
sure on the valve seat)
• Numerous functions can be activated by simple configuring
(e.g. characteristics and limits)
• Extensive diagnosis functions for valve and actuator
• Only one device version for linear and part-turn actuators
• Few moving parts, hence insensitive to vibrations
• External non-contacting position sensor as option for extreme
ambient conditions
• Partial Stroke Test e.g. for safety valves
• SIL (Safety Integrity Level) 2
• Can also be operated with natural gas
SIPART PS2 electropneumatic positioner
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Application
The SIPART PS2 positioner is used, for example, in the following
industries:
• Chemical/petrochemical
• Power stations
• Paper and glass
• Water, waste water
• Food and pharmaceuticals
• Offshore plants
The SIPART PS2 positioner is available:
• For single-action actuators: in plastic, stainless steel or alumi-
num casings, as well as flameproof aluminium casing (EEx d)
• For double-action actuators: in plastic and stainless steel cas-
ing, as well as flameproof aluminum casing (EEx d)
• For non-hazardous applications
• For hazardous applications in the designs
- as intrinsically-safe device (EEx ia/ib) or
- in flameproof aluminum casing (EEx d) or
- in EEx n design (non sparking)
and in the versions:
• 0/4 to 20 mA control communication without/with communica-
tion through HART signal
• With PROFIBUS PA communication interface
• With FOUNDATION Fieldbus (FF) communications interface.
Explosion-proof versions
The basic version of the device is available in an intrinsically-
safe design with degree of protection EEx ia/ib or in a design
with approval for zone 2/zone 22 (dust).
Operation in zone 1 is permitted when enclosed in the flame-
proof casing version SIPART PS2 EEx d. (see "Technical Data").
It is then permissible to use all option modules (except external
actuator travel detection systems, SIA module, limit value con-
tact module and NCS).
Stainless steel casing for extreme ambient conditions
The SIPART PS2 is available in a stainless steel casing (without
window in the lid) for use in particularly aggressive environments
(e.g. offshore operation, chlorine plants etc.). The device func-
tions are the same as those of the basic versions.
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SIPART PS2 EEx d electropneumatic positioner in flameproof casing
SIPART PS2 in stainless steel casing
The SIPART PS2 electropneumatic positioner is used to control
the final control element of pneumatic linear or part-turn actua-
tors. The electropneumatic positioner moves the actuator to a
valve position corresponding to the setpoint. Additional function
inputs can be used to block the valve or to set a safety position.
A binary input is present as standard in the basic device for this
purpose.
Siemens FI 01 · 2008
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© Siemens AG 2007
Electropneumatic positioners
SIPART PS2
Technical description
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Design
The SIPART PS2 positioner is a digital field device with a highly-
integrated microcontroller.
The positioner consists of the following components:
• Casing and cover
• PCB with corresponding electronics with or without communi-
cation through HART
or with electronics for communication in accordance with
- PROFIBUS PA specification, IEC 61158-2; bus-supplied de-
vice, or
- FOUNDATION Fieldbus (FF) specification, IEC 61158-2,
bus-supplied device
• Actuator travel detection system
• Terminal housing with screw terminals
• Pneumatic valve manifold with piezoelectric valve precontrol.
The valve manifold is located in the housing, the pneumatic con-
nections for the inlet air and the positioning pressure on the right-
hand side. A pressure gauge block and/or a safety solenoid
valve can be connected there as options. The SIPART PS2 posi-
tioner is fitted to the linear or part-turn actuator using an appro-
priate mounting assembly. The circuit board container in the
casing provides slots for separately ordered boards with the
following functions:
I
y
module:
• Position feedback as a two-wire signal 4 to 20 mA.
Alarm module (3 outputs, 1 input):
• Signaling of two limits of the travel or angle by binary signals.
The two limits can be set independently as maximum or mini-
mum values.
• Output of an alarm if the setpoint position of the final control
element is not reached in automatic mode or if a device/fitting
fault occurs.
• Second binary input for alarm signals of for triggering safety
reactions e. g. for blocking function or safety position.
Limit signaling through slot-type initiators (SIA module)
Two limits can be signaled redundantly as NAMUR signals
(EN 60947-5-6) by slot-type initiators. The module also contains
an alarm output (see Alarm module).
Limit value signal via mechanical contacts (Limit value con-
tact module)
Two limits can be signaled redundantly by switching contacts. A
fault message output is also integrated in the module (see alarm
module).
Valid for all modules described above:
All signals are electrically isolated from one another and from the
basic unit. The outputs indicate self-signaling faults. The mod-
ules are easy to retrofit.
Separate mounting of actuator travel detection system and
controller unit
The actuator travel detection system and controller unit can be
connected separately for all casing versions of the SIPART PS2
(except flameproof design). Measurement of the travel or angle
is carried out directly on the actuator. The controller unit can then
be fitted a certain distance away, e.g. on a mounting pipe or sim-
ilar, and is connected to the travel detection system by an elec-
tric cable and to the actuator by one or two pneumatic lines.
Such a split design is frequently advantageous if the ambient
conditions at the fitting exceed the specified values for the posi-
tioner (e.g. strong vibrations).
The following can be used for measuring the travel or angle:
• NCS sensor
• External position detection system C73451-A430-D78
• A commercially available potentiometer (10 k
required by the linear potentiometer is very small and, on the other,
the transmission characteristic is optimum for a small travel.
Separate connection of actuator travel detection system and controller unit
Non-contacting position sensor (NCS)
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Contact and non-contacting positioning sensor (NCS) for part-turn actu-
ator (left) and for linear actuator 14 mm (0.55 inch) (right)
resistance)
(e.g. for higher application temperatures or customer-specific
applications)
The use of linear potentiometers is recommended for very small ac-
tuators with a short valve travel since, on the one hand, the space
Ω
NCS for travels >14 mm (0.55 inch)
The NCS sensor consists of a non-contacting position sensor. All
coupling elements are omitted such as coupling wheel and
driver pin with part-turn actuators or lever and pick-up bracket
with linear actuators up to 14 mm travel.
This results in:
• Even greater resistance to vibration and shock
• No wear of sensor
• Problem-free mounting on very small actuators
• Negligible hysteresis with very small travels.
The sensor does not require an additional power supply, i.e.
SIPART PS2 (not for EEx d version) can be operated in a 2-wire
system. The NCS (
N
on
C
ontacting Position
S
ensor) consists of a
potted sensor housing which must be mounted permanently and
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Siemens FI 01 · 2008
© Siemens AG 2007
Electropneumatic positioners
SIPART PS2
Technical description
a magnet which is mounted on the spindle of linear actuators or
on the shaft butt of part-turn actuators. For the version for travels
>14 mm (0.55 inch), the magnet and the NCS are premounted
on a stainless steel frame and offer the same interface mechan-
ically as the positioner itself, i.e. they can be mounted using the
standard mounting kits 6DR4004-8V, -8VK and -8VL.
The installation of a EMC filter module in the positioner (controller
unit) is necessary in order to ensure a connection level with EMC
according to EN 61326/A1 and NAMUR NE21 when using exter-
nal sensors (see Ordering data for "EMC filter module")
When operating the SIPART PS2 through the HART interface, the
connection is made directly to the 2-wire cable to the
SIPART PS2 positioner through a HART modem that can be con-
nected to the RS 232 or USB interface. The signals needed for
communication in conformity with the HART protocol are super-
imposed on the current signal in accordance with the
F
requency
S
hift
K
eying (FSK) method.
Automatic commissioning
With a simple configuration menu the SIPART PS2 can be quickly
adapted to the fitting and adjusted by means of an automatic
startup function.
During initialization, the microcontroller determines the zero
point, full-scale value, the direction of action and the positioning
speed of the fitting. From this data it establishes the minimum
pulse time and the dead zone, thus optimizing the control.
Low air consumption
A hallmark of the SIPART PS2 is its own extremely low consump-
tion of air. Normal air losses on conventional positioners are very
costly. Thanks to the use of modern piezoelectric technology, the
SIPART PS2 consumes air only when it is needed, which means
that it pays for itself within a very short time
Comprehensive monitoring functions
The SIPART PS2 has various monitoring functions with which
changes on the actuator and valve can be detected and sig-
naled if applicable when a selectable limit has been exceeded.
This information may be important for diagnosis of the actuator
or valve. The measured values to be determined and monitored,
some of whose limits can be adjusted, include:
• Travel integral
• Number of changes in direction
• Alarm counter
• Self-adjusting dead zone
• Valve end limit position (e.g. for detection of valve seat wear
or deposits)
• Operating hours (also according to temperature and position-
ing ranges) as well as min./max. temperature
• Operating cycles of piezoelectric valves
• Valve positioning time
• Actuator leakages
Status monitoring with 3-stage alarm concept
The intelligent electropneumatic SIPART PS2 positioner is
equipped with additional monitoring functions. The status indi-
cations derived from these monitoring functions signal active
faults of the unit. The severity of these faults are graded using
"traffic light signaling", symbolized by a wrench in the colors
green, yellow and red (with SIMATIC PDM and Maintenance Sta-
tion):
• Need for maintenance (green wrench)
• Urgent need for maintenance (yellow wrench)
• Imminent danger of unit failure or general failure (red wrench)
This allows users to put early measures into action in the run-up
to a serious valve or actuator fault, which can prevent an immi-
nent system shutdown. The fact that a fault indication is sig-
naled, such as the onset of a diaphragm break in the actuator or
the progressive sluggishness of a unit, enables the user to en-
sure system reliability at any time by means of suitable mainte-
nance strategies.
This three-stage alarm hierarchy also allows early detection and
signaling of other faults, such as the static friction of a packing
box, the wearing of a valve plug/seating, or precipitations or in-
crustations on the fittings.
These fault indications can be output either line-conducted over
the alarm outputs (see above) of the positioner (max. 3), or via
communication over the HART or fieldbus interfaces. In this
case, the HART, PROFIBUS and FF versions of SIPART PS2 per-
mit a differentiation of the various fault indications, as well as a
trend representation and histogram function of all key process
variables with regard to the fittings.
The LCD of the device also displays the graded maintenance re-
quirements, complete with identification of the source of the fault.
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Function
The SIPART PS2 electropneumatic positioner works in a com-
pletely different way to normal positioners.
Mode of operation
Comparison of the setpoint and the actual value takes place
electronically in a microcontroller. If the microcontroller detects a
deviation, it uses a 5-way switch procedure to control the piezo-
electric valves, which regulates the flow of air into and from the
chambers of the pneumatic actuator or blows it in the opposite
direction.
The microcontroller then outputs an electric control command to
the piezoelectric valve in accordance with the size and direction
of the deviation (deviation between setpoint w and control output
x). The piezoelectric valve converts the command into a pneu-
matic positional increment.
The positioner outputs a continuous signal in the area where
there is a large control deviation (high-speed zone); in areas of
moderate control deviation (slow-speed zone) it outputs a se-
quence of pulses. No positioning signals are output in the case
of a small control deviation (adaptive or variable dead zone).
The linear or rotary motion of the actuator is detected by the
mounting assembly and transferred to a high-quality potentio-
meter made of plastic conductive material over a shaft and a
non-floating gear transmission.
The angular error of the pick-up in cases where the assembly is
mounted on a linear actuator is corrected automatically.
When connected in a 2-wire system, the SIPART PS2 draws its
power exclusively from the 4 to 20 mA setpoint signal. The elec-
tric power is also connected through the 2-wire bus signal with
PROFIBUS operation (SIPART PS2 PA). The same applies for the
FOUNDATION Fieldbus version.
Pneumatic valve manifold with piezoelectric valve precontrol
The piezoelectric valve can release very short control pulses.
This helps achieve a high positioning accuracy. The pilot ele-
ment is a piezoelectric bending converter which switches the
pneumatic main control unit. The valve manifold is characterized
by an extremely long service life.
Local operation
Local operation is performed using the built-in LCD and the
three input keys. Switching between the operating levels Auto-
matic, Manual, Configuring and Diagnosis is possible at the
press of a button.
In Manual mode the drive can be adjusted over the entire range
without interrupting the circuit.
Operation and monitoring with the SIMATIC PDM communi-
cations program
The SIMATIC PDM program is available for communication
through the HART interface and also for the PROFIBUS PA cou-
pling.
The SIMATIC PDM communications software permits easy re-
mote operation and monitoring using a PC or laptop. The posi-
tioner can also be configured using this program. Parameters
which provide important information for maintenance and fault
diagnosis of the complete unit can also be determined using
process data and comparison data.
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