Circuit Description - Siemens 7MF4333 User Manual

UMSITRAPDS3-1

8.0 CIRCUIT DESCRIPTION

This section provides a basic circuit description of the SITRANS P DSIII Pressure Transmitter. Figure 8-
1 shows the functional block diagram. Basically the transmitter consists of two active components: a
measuring cell and an electronics module. Input pressure is piped to the measuring cell (1) that includes
diaphragms, fill fluid, and related components. The output signal from the measuring cell goes to the
electronics module that consists of the microcontroller (4), A/D (3) and D/A (5) converters, HART
modem (7), and related components. The magnetic pushbuttons (8) and display (9) connect to the
electronics module.
The transmitter family consists of four model types: flow, differential pressure, absolute pressure, and
flange-mounted liquid level. All models use the same interchangeable electronics module, display,
enclosure, and magnetic pushbuttons. The major difference between models is the measuring cell.
The transmitters can communicate with a Model 275 HART Communicator, Model 375 Field
Communicator, or a Primary Master controller using the HART protocol.
1 Measuring cell sensor
2 Instrument amplifier
3 Analog-digital converter
4 Microcontroller
5 Digital-analog converter
6 Two non-volatile memories in the measuring
cell and electronics
November 2010
FIGURE 8-1 Transmitter Block Diagram
7 HART modem
8 Magnetic pushbuttons for local operation
9 Digital display
10 Analog output test terminals
I Output current
A
U Power supply
H
Circuit Description
8-1