VEGA VEGABAR 74 4 … 20 mA_HART - Manual (Page 9)

3 .2 Principle of operation
VEGABAR 74 is a pressure transmitter for use in the paper,
food processing and pharmaceutical industry. Thanks to the
high protection class IP 68/IP 69K it is particularly suitable for
use in humid environment. Depending on the version, it is used
for level, gauge pressure, absolute pressure or vacuum
measurements. Measured products are gases, vapours and
liquids, also with abrasive contents.
T he sensor element is the CERTEC ® measuring cell with
flush, abrasion resistant ceramic diaphragm. The hydrostatic
pressure of the medium or the process pressure causes a
capacitance change in the measuring cell via the diaphragm.
T
his change is converted into an appropriate output signal and
outputted as measured value.
T
he CERTEC ® measuring cell is also equipped with a
temperature sensor. The temperature value can be processed
via the signal output.
T wo-wire electronics 4 … 20 mA/HART for power supply and
measured value transmission over the same cable.
T he supply voltage range can differ depending on the
instrument version.
T
he data for power supply are stated in chapter "Technical
data" in the "Supplement".
3 .3 Operation
VEGABAR 74 4 … 20 mA/HART can be adjusted with different
adjustment media:
l
with external adjustment/indication VEGADIS 12
l
an adjustment software according to FDT/DTM standard,
e.g. PACTware™ and PC
l
with a HART handheld
T
he kind of adjustment and the adjustment options depend on
the selected adjustment component. The entered parameters
are generally saved in the respecitive sensor, when adjusting
with PACTware™ and PC optionally also in the PC.
Area of application
Functional principle
Supply
VEGABAR 74 - 4 … 20 mA/HART 9
P roduct description
28432
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EN
-070718