Siemens SITRANS P - Manual (Page 146)

SITRANS P measuring instruments for pressure
Transmitters for hydrostatic level
MPS series (submersible sensor)
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Overview
SITRANS P pressure transmitters, MPS series (submersible sensor)
SITRANS P pressure transmitters, MPS series, are submersible
sensors for hydrostatic level measurements.
The pressure transmitters of the MPS series are available for var-
ious measuring ranges and with explosion protection as an op-
tion.
A junction box and a cable hanger are available as accessories
for simple installation.
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Benefits
• Compact design
• Simple installation
• Small error in measurement (0.3%)
• Degree of protection IP68
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Application
SITRANS P pressure transmitters, MPS series, are used in the
following branches for example:
• Oil and gas industries
• Shipbuilding
• Water supply
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Design
SITRANS P pressure transmitters, MPS series, have a flush-
mounted piezo-resistive sensor with stainless steel diaphragm.
These pressure transmitters are equipped with an electronic cir-
cuit fitted together with the sensor in a stainless steel housing.
The cable also contains a strength cord and vent pipe.
The diaphragm is protected against external influences by a
protective cap.
The sensor, electronic circuit and cable are sealed in a common
housing of small dimensions.
The pressure transmitter is temperature-compensated for a wide
temperature range.
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Function
SITRANS P pressure transmitters, MPS series, are for measuring
the liquid levels in wells, tanks, channels and dams.
SITRANS P pressure transmitters, MPS series, mode of operation and
wiring diagram
On one side of the sensor, the diaphragm is exposed to the hy-
drostatic pressure which is proportional to the submersion
depth. This pressure is compared with atmospheric pressure.
Pressure compensation is carried out using the vent pipe in the
connection cable.
The hydrostatic pressure of the liquid column acts on the sensor
diaphragm, and transmits the pressure to the piezo-resistive
bridge in the sensor.
The output voltage of the sensor is applied to the electronic cir-
cuit where it is converted into an output current of 4 to 20 mA.
The cable of the 7MF1570 transmitter must always be connected
in the supplied junction box. The junction box has to be installed
near the measuring point.
If the medium is anything other than water, it is also necessary to
check compatibility with the specified materials of the transmit-
ter.
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Integration
Junction box 7MF1570-8AA, opened
p
I
0
, U
B
U
const.
U
I
EM
+2 (brown)
-1 (blue)
Vent pipe
Screen
Diaphragm
Sensor
© Siemens AG 2008