Measuring Cell For Gauge Pressure, Front-Flush Membrane; Measuring Cell For Absolute Pressure, Front-Flush Membrane - Siemens SITRANS P DS III Operating Instructions Manual

Description
3.6 Principle of operation
3.6.3.6

Measuring cell for gauge pressure, front-flush membrane

①
②
③
④
Figure 3-12
The inlet pressure (p
④
the resistance of the four piezoresistors (bridge circuit) of the gauge pressure sensor. The
change in the resistance causes a bridge output voltage proportional to the inlet pressure.
Transmitters with measuring span ≤ 63 bar measure the inlet pressure against atmosphere,
those with measuring spans ≥ 160 bar against vacuum.
3.6.3.7

Measuring cell for absolute pressure, front-flush membrane

①
②
③
Figure 3-13
34
Reference pressure opening
Measuring cell
Process connection
Seal diaphragm
Function chart of the measuring cell for gauge pressure, flush mounted diaphragm
) is transferred to the gauge pressure sensor
e
⑤
and the filling liquid
Measuring cell
Process connection
Seal diaphragm
Function chart of the measuring cell for absolute pressure, flush mounted diaphragm
⑤
⑥
p
e
, displacing its measuring diaphragm. The displacement changes
④
⑤
p
e
Filling liquid
Gauge pressure sensor
Inlet pressure
⑥
via the seal diaphragm
Filling liquid
Absolute pressure sensor
Inlet pressure
SITRANS P DS III with PROFIBUS PA
Operating Instructions, 06/2013, A5E00053276-07