Measuring Cell For Differential Pressure And Flow Rate - Siemens Sitrans P500 Operating Instructions Manual

3.5.2.1

Measuring cell for differential pressure and flow rate

①
②
③
④
⑤
Figure 3-6
● The differential pressure is transmitted via the seal diaphragm
the silicon pressure sensor
● If the measuring limits are exceeded, the overload diaphragm
diaphragm
pressure sensor
● Differential pressure causes the measuring diaphragm of the silicon pressure sensor to
be displaced. The displacement changes the resistance value of the four doped piezo
resistors arranged in a bridge circuit in the measurement diaphragm.
● The change in resistance causes the bridge output voltage to vary in proportion to the
differential pressure.
SITRANS P500 with HART
Operating Instructions, 12/2014, A5E02344528-09
Silicon pressure sensor
Inlet pressure P
+
Process flange with process connection
O-ring
Measuring cell body
Function diagram of the measuring cell for differential pressure and flow rate
⑧
touches the body of the measuring cell
①
against overload.
⑥
⑦
⑧
⑨
①
.
3.5 Functional principle
Overload diaphragm
Filling liquid
Seal diaphragm
Inlet pressure P
-
⑧
and the fill fluid
⑥
flexes until the seal
⑤
. This protects the silicon
Description
⑦
to
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