Siemens SITRANS P Brochure & Specs page 32

SITRANS P measuring instruments for pressure
Transmitters for food, pharmaceuticals and biotechnology
SITRANS P300 for gage and absolute pressure
The input pressure (pe) is transferred to the absolute pressure
sensor (5) via the seal diaphragm (3) and the filling liquid (4),
displacing its measuring diaphragm. The displacement
changes the resistance value of the four piezo resistors in the
measuring diaphragm in a bridge circuit. The change in the re-
sistance causes a bridge output voltage proportional to the input
2
pressure.
Parameterization of SITRANS P300
Depending on the version, there are a range of options for pa-
rameterizing the pressure transmitter and for setting or scanning
the parameters.
Parameterization using the input keys (local operation)
With the input keys you can easily set the most important param-
eters without any additional equipment.
Parameterization using HART communication
Parameterization using HART communication is performed with
a HART communicator or a PC.
Communication between a HART communicator and a pressure transmit-
ter
When parameterizing with the HART communicator, the connec-
tion is made directly to the 2-wire system.
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 cur-
rent using the Frequency Shift Keying (FSK) method.
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© Siemens AG 2008
Adjustable parameters on SITRANS P300 with HART communi-
cation
Parameters
Start of scale
Full-scale value
Electrical damping
Start-of-scale value without application
of a pressure ("Blind setting")
Full-scale value without application of a
pressure ("Blind setting")
Zero adjustment
Current transmitter
Fault current
Disabling of keys, write protection
Type of dimension and actual dimension x
Input of characteristic
Freely-programmable LCD
Diagnostics functions
1)
Cancel apart from write protection
Diagnostic functions for SITRANS P300 with HART communica-
tion
• Zero correction display
• Event counter
• Limit transmitter
• Saturation alarm
• Slave pointer
• Simulation functions
• Maintenance timer
Available physical units of display for SITRANS P300 with HART
communication
Physical variable
Pressure (setting can also be made
in the factory)
Level (height data)
Volume
Mass
Temperature
Miscellaneous
Input keys HART com-
munication
x x
x x
x x
x x
x x
x x
x x
x x
1)
x x
x
x
x
x
Physical dimensions
Pa, MPa, kPa, bar, mbar, torr, atm,
2 2
psi, g/cm , kg/cm , inH O, inH O
2 2
(4 °C), mmH O, ftH O (20 °C),
2 2
inHg, mmHg
m, cm, mm, ft, in
3 3 3 3 3
m , dm , hl, yd , ft , in , US gal-
lon, lmp. gallon, bushel, barrel,
barrel liquid
g, kg, t, lb, Ston, Lton, oz
K, °C, °F, °R
%, mA