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4.4.2.7
Measuring cell for level
①
Inlet pressure P
+
⑦
Overload diaphragm
②
Seal diaphragm on the measuring cell
⑧
Inlet pressure P
-
③
Pressure cap
⑨
Filling liquid of the measuring cell
④
O-ring
⑩
Capillary tube with the fill fluid of the mounting
flange
⑤
Differential pressure sensor
⑪
Flange with a tube
⑥
Measuring cell body
⑫
Seal diaphragm on the mounting flange
Figure 4-13
Function chart of the measuring cell for level
● The inlet pressure (hydrostatic pressure)
①
works hydraulically on the measuring cell
through the seal diaphragm on the mounting flange
⑫
.
● The differential pressure at the measuring cell is transmitted to the differential pressure
sensor
⑤
through the seal diaphragms
②
and the filling liquid
⑨
.
● When measuring limits are exceeded, the overload diaphragm
⑦
is displaced until one of
the seal diaphragms
②
or
⑫
rests on the measuring cell body
⑥
. The seal diaphragms
②
thus protect the differential pressure sensor
⑤
from overload.
● The seal diaphragm
②
is displaced by the differential pressure. The displacement changes
the resistance of the four doped piezoresistors in the bridge circuit.
● The change in the resistance causes a bridge output voltage proportional to the differential
pressure.
4.5
System configuration
Introduction
The pressure transmitter can be used in a number of system configurations:
● As a stand-alone version, supplied with the necessary auxiliary power
● As part of a complex system environment, e.g. SIMATIC S7
Description
4.5 System configuration
SITRANS P320/P420 with 4 to 20 mA/HART
38
Operating Instructions, 11/2019, A5E44852162-AC
Содержание SITRANS P
Страница 10: ...Table of contents SITRANS P320 P420 with 4 to 20 mA HART 10 Operating Instructions 11 2019 A5E44852162 AC ...
Страница 272: ...Abbreviations SITRANS P320 P420 with 4 to 20 mA HART 272 Operating Instructions 11 2019 A5E44852162 AC ...
Страница 280: ...Index SITRANS P320 P420 with 4 to 20 mA HART 280 Operating Instructions 11 2019 A5E44852162 AC ...