SIEMENS Pressure measurement SITRANS P310 Technical description

SITRANS P310 pressure transmitters are digital pressure transmitters featuring extensive user-friendliness and best in class performance with up to 0.075 % high accuracy. The parameterization is performed using control keys or via HART interface.

Transmitters with type of NEPSI protection “Intrinsic safety” and “Explosion-proof” may be installed within potentially explosive atmospheres (zone 1) or in zone 0.

Range ability up to 100:1.

Transmitters are available for measuring pressure, level and flow according to customer requirement.

Application

The pressure transmitters of the DS III series, can be used in industrial areas with extreme chemical and mechanical loads. Electromagnetic compatibility in the range 10 kHz to 1 GHz makes the DS III pressure transmitters suitable for locations with high electromagnetic emissions.

Pressure transmitters with type of protection “Explosion-proof” may be installed in hazardous areas (zone 1) or in zone 0. The pressure transmitters are provided with an EC type examination certificate and comply with the corresponding harmonized European standards (ATEX).

Pressure transmitters with the type of protection “Intrinsic safety” for use in zone 0 may be operated with power supply units of category “ia” and “ib”.

The transmitters can be equipped with various designs of remote seals for special applications such as the measurement of highly viscous substances.

The pressure transmitter can be programmed locally using the 3 control buttons or externally via HART or PROFIBUS PA or FOUNDATION Fieldbus interface.

Pressure transmitters for gauge pressure

Measured variable: Gauge pressure of corrosive and non-corrosive gases, vapors and liquids.

Span (infinitely adjustable)
for DS III with HART: 0.01 bar to 700 bar (0.15 psi to 10153 psi)

Nominal measuring range
for DS III with PROFIBUS PA and FOUNDATION Fieldbus: 1 bar to 700 bar (14.5 psi to 10153 psi)

Pressure transmitters for absolute pressure

Measured variable: Absolute pressure of corrosive and non-corrosive gases, vapors and liquids.

Span (infinitely adjustable)
for DS III with HART: 8.3 mbar a to 100 bar a (0.12 to 1450 psia)

Nominal measuring range
for DS III with PROFIBUS PA and FOUNDATION Fieldbus: 250 mbar a to 100 bar a (3.6 to 1450 psia)

There are two series:

  • Gauge pressure series
  • Differential pressure series
Pressure transmitters for differential pressure and flow

Measured variables:

  • Differential pressure
  • Small positive or negative overpressure
  • Flow q ~ √Δp (together with a primary differential pressure device (see section “Flowmeters”))

Span (infinitely adjustable)
for DS III with HART: 1 mbar to 30 bar (0.0145 to 435 psi)

Nominal measuring range
for DS III with PROFIBUS PA and FOUNDATION Fieldbus: 20 mbar to 30 bar (0.29 to 435 psi)

Pressure transmitters for level

Measured variable: Level of corrosive and non-corrosive liquids in open and closed vessels.

Span (infinitely adjustable)
for DS III with HART: 25 mbar to 5 bar (0.363 to 72.5 psi)

Nominal measuring range
for DS III with PROFIBUS PA and FOUNDATION Fieldbus: 250 mbar to 5 bar (3.63 to 72.5 psi)

Nominal diameter of the mounting flange

  • DN 80 or DN 100
  • 3-inch or 4-inch

In the case of level measurements in open containers, the low-pressure connection of the measuring cell remains open (measurement “compared to atmospheric”).

In the case of measurements in closed containers, the lower-pressure connection has to be connected to the container in order to compensate the static pressure.

The wetted parts are made from a variety of materials, depending on the degree of corrosion resistance required.

Design

Front view

The transmitter consists of various components depending on the order. The possible versions are listed in the ordering information. The components described below are the same for all transmitters.

The rating plate (7, Figure “Front view”) with the Article No. is located on the side of the housing. The specified number together with the ordering information provides details on the optional design details and on the possible measuring range (physical properties of built-in sensor element).

The approval label is located on the opposite side.

The housing is made of die-cast aluminum. A round cover is screwed on at the front and rear of the housing. The front cover (2) can be fitted with a viewing pane so that the measured values can be read directly on the display. The inlet (8) for the electrical connection is located either on the left or right side. The unused opening on the opposite side is sealed by a blanking plug. The protective earth connection is located on the rear of the housing.

The electrical connections for the power supply and screen are accessible by unscrewing the rear cover. The bottom part of the housing contains the measuring cell with process connection (5). The measuring cell is prevented from rotating by a locking screw (4).

At the top of the housing is a plastic cover (1), which hides the input keys.

Benefits

  • High quality and service life
  • High reliability even under extreme chemical and mechanical loads
  • For corrosive and non-corrosive gases, vapors and liquids
  • Extensive diagnostics and simulation functions
  • Separate replacement of measuring cell and electronics without recalibration
  • Minimal conformity error
  • Good long-term stability
  • Wetted parts made of high-grade materials (e.g., stainless steel, Hastelloy, Gold Monel, Tantalum)
  • Infinitely adjustable spans from 0.01 bar to 700 bar (0.15 psi to 10153 psi) for DS III with HART interface
  • Nominal measuring ranges from 1 bar to 700 bar (14.5 psi to 10153 psi) for DS III with PROFIBUS PA and FOUNDATION Fieldbus interface
  • Highly accurate measurement
  • Parameter assignment using input buttons and HART, PROFIBUS PA or FOUNDATION Fieldbus interface.

Function

Mode of operation of the measuring cells

Measuring cell for gauge pressure

Measuring cell for gauge pressure, function diagram

The pressure pe is applied through the process connection (2, “Measuring cell for gauge pressure, function block diagram”) to the measuring cell (1). This pressure is subsequently transmitted further through the seal diaphragm (3) and the filling liquid (4) to the silicon pressure sensor (5) whose measuring diaphragm is then flexed. This changes the resistance of the four piezo-resistors fitted in the diaphragm in a bridge circuit. This change in resistance results in a bridge output voltage proportional to the absolute pressure.

Measuring cell for differential pressure and flow

Measuring cell for differential pressure and flow, function diagram

The differential pressure is transmitted through the seal diaphragms (1, Figure “Measuring cell for differential pressure and flow, function diagram”) and the filling liquid (7) to the silicon pressure sensor (4).

The measuring diaphragm is flexed by the applied differential pressure. This changes the resistance of the four piezo-resistors fitted in the diaphragm in a bridge circuit. This change in resistance results in a bridge output voltage proportional to the absolute pressure.

An overload diaphragm is installed to provide protection from overloads. If the measuring limits are exceeded, the overload diaphragm (3) is flexed until the seal diaphragm rests on the body of the measuring cell (6), thus protecting the silicon pressure sensor from overloads.

Parameterization P310

Depending on the version, there are a range of options for parameterizing the pressure transmitter and for setting or scanning the parameters.

Parameterization using the input buttons (local operation)

With the input buttons you can easily set the most important parameters without any additional equipment.

Parameterization using HART

Parameterization using HART is performed with a HART Communicator or a PC.

Communication between a HART Communicator and a pressure transmitter

When parameterizing with the HART Communicator, the connection is made directly to the 2-wire cable.

HART communication between a PC communicator and a pressure transmitter

When parameterizing with a PC, the connection is made through a HART modem.

The signals needed for communication in conformity with the HART 5.x or 6.x protocols are superimposed on the output current using FSK (Frequency Shift Keying).

Adjustable parameters, P310 with HART

Parameters

Input keys (P310 with HART)

HART communication

Start of scale

x

x

Full-scale value

x

x

Electrical damping

x

x

Start-of-scale value without application of a pressure (“Blind setting”)

x

x

Full-scale value without application of a pressure (“Blind setting”)

x

x

Zero adjustment

x

x

Current transmitter

x

x

Fault current

x

x

Disabling of buttons, write protection

x

1)

Type of dimension and actual dimension

x

x

Characteristic (linear / square-rooted)

2)

2)

Input of characteristic

x

Freely-programmable LCD

x

Diagnostic functions

x

1) Cancel apart from write protection

2) Differential pressure only

Available physical units of display for P310 with HART

Physical quantity

Physical units

Pressure (setting can also be made in the factory)

Pa, MPa, kPa, bar, mbar, torr, atm, psi, g/cm2, kg/cm2, inH2O, inH2O (4 °C), mmH2O, ftH2O (20 °C), inHg, mmHg

Level (height data)

m, cm, mm, ft, in

Volume

m3, dm3, hl, yd3, ft3, in3, US gallon, lmp. gallon, bushel, barrel, barrel liquid

Mass

g, kg, t, lb, Ston, Lton, oz

Volume flow

m3/d, m3/h, m3/s, l/min, l/s, ft3/d, ft3/min, ft3/s, US gallon/min, US gallon/s

Mass flow

t/d, t/h, t/min, kg/d, kg/h, kg/min, kg/s, g/d, g/h, g/min, g/s, lb/d, lb/h, lb/min, lb/s, LTon/d, LTon/h, STon/d, STon/h, STon/min

Temperature

K, °C, °F, °R

Miscellaneous

%, mA