SITRANS P310, Technical description Siemens

Область применения



SITRANS P310 pressure transmitters are particularly suited for use in the industrial areas of Energy, Oil & Gas as well as Water/Wastewater. Electromagnetic compatibility in the range 10 kHz to 1 GHz makes them 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 operated locally over 3 input buttons or programmed externally over HART interface.

Pressure transmitters for gauge pressure

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

Measuring span (continuously adjustable) 0.01 bar to 700 bar (0.15 psi to 10153 psi)

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"))

Measuring span (continuously adjustable) 1 mbar to 30 bar (0.0145 to 435 psi)

Обзор



SITRANS P310 pressure transmitters are digital pressure transmitters with a high level of operating convenience. With a measurement accuracy of 0.075%, they complement the SITRANS P DS III and round off the portfolio. The parameterization is performed using input buttons or the HART interface.

The comprehensive functionality makes for precise adjustment of the pressure transmitter to the requirements of the plant. Operation is very simple, despite the variety of setting options.

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

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

SITRANS P310 pressure transmitters are available in various versions for measuring:

  • Gauge pressure
  • Differential pressure
  • Volume flow
  • Mass flow

Дизайн



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 Order No. is located on the side of the housing. The specified number together with the ordering information provide 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 or stainless steel precision casting. 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). As the result of this modular design, the measuring cell and the electronics can be replaced separately from each other. The set parameter data are retained.

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

Example of screwed-on measuring point label

Функции



Operation of electronics with HART communication

Function diagram of electronics

The bridge output voltage created by the sensor (1, Figure "Function diagram of electronics") is amplified by the measuring amplifier (2) and digitized in the analog-to-digital converter (3). The digital information is evaluated in a microcontroller, corrected for linearity and temperature response, and converted in a digital-to-analog converter (5) into an output current of 4 to 20 mA.

The diode circuit (10) protects against incorrect polarity.

The data specific to the measuring cell, the electronics data, and the parameter data are stored in the two non-volatile memories (6). One memory is coupled to the measuring cell, the other to the electronics. As the result of this modular design, the electronics and the measuring cell can be replaced separately from each other.

Using the 3 input buttons (8) you can parameterize the pressure transmitter directly at the measuring point. The input buttons can also be used to control the view of the measurement results, the error messages and the operating modes on the display (9).

The HART modem (7) permits parameterization using a protocol according to the HART specification.

The pressure transmitters with spans ≤ 63 bar measure the input pressure compared to atmosphere, transmitters with spans ≥ 160 bar compared to vacuum.

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 diagram") to the measuring cell (1). This pressure is subsequently transmitted further through the seal diaphragm (3) and the fill fluid (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 rate

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 fill fluid (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 differential 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 of SITRANS 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 SITRANS P310 parameters with HART

Parameter

Input buttons (DS III with HART)

HART communication

Start of scale

x

x

Full scale value

x

x

Electrical damping

x

x

Blind adjustment of the start of scale value

x

x

Blind adjustment of the full scale value

x

x

Zero-point adjustment

x

x

Current simulator

x

x

Fault current

x

x

Keyboard lock and write protection

x

x 1)

Type of unit, unit

x

x

Characteristic (linear / square-rooted)

x 2)

x 2)

Input of characteristic

 

x

Freely-programmable LCD

 

x

Diagnostic functions

 

x



1) Cancel apart from write protection

2) Only differential pressure

Available physical units of display for SITRANS P310 with HART

Physical variable

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

Weight

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

Other

%, mA



Особенности


  • High quality and service life
  • High reliability even under extreme chemical and mechanical loads
  • For aggressive and non-aggressive gases, vapors and liquids
  • Extensive diagnostics and simulation functions
  • Good long-term stability
  • Wetted parts made of high-grade materials (stainless steel, Hastelloy)
  • Infinitely adjustable spans from 0.01 bar to 700 bar (0.15 psi to 10153 psi)
  • Measuring accuracy 0.075 %
  • Parameterization over input buttons and HART interface