VEGA VEGABAR 87 Save sensor - Operating Instructions - Manual (Page 10)

10
3 Product description
VEGABAR 87 • Slave sensor for electronic differential pressure
45053-EN-131011
4 3 2 1
Fig. 3: Configuration of the METEC ® measuring cell with VEGABAR 87
1 Process diaphragm
2 Isolating liquid
3 FeNi adapter
4 CERTEC ® measuring cell
The measuring cell design depends on the selected pressure type.
Relative pressure: the measuring cell is open to atmosphere. The
ambient pressure is detected in the measuring cell and compensated.
It thus has no influence on the measured value.
Absolute pressure: the measuring cell is evacuated and encapsu-
lated. The ambient pressure is not compensated and does hence
influence the measured value.
Relative pressure, climate-compensated: the measuring cell is
evacuated and encapsulated. The ambient pressure is detected
through a reference sensor in the electronics and compensated. It
thus has no influence on the measured value.
The process pressure acts on the sensor element via the stainless
steel diaphragm and an internal transmission liquid. The process
pressure causes a resistance change which is converted into a cor-
responding output signal and outputted as measured value.
The METEC
® measuring cell is the measuring unit. It consists of
the ceramic-capacitive CERTEC ® measuring cell and a special,
temperature-compensated isolating system.
Pressure types
Measuring system