VEGA VEGABAR 24 - Manual (Page 4)

4 VEGABAR 24
Product description
1 Product description
1.1 Function and configuration
The VEGABAR 24 process pressure trans-
mitters are efficient instruments for process
pressure measurement. The dry CERTEC
®
ceramic-capacitive measuring cell is used as
a pressure sensor element. The process
pressure causes a capacitance change
within the measuring cell via the diaphragm.
This capacitance change is detected by an
ASIC (application specific integrated circuit)
and converted into a pressure proportional
signal by an integral oscillator with microcom-
puter. Precise digital processing of meas-
ured data with highest resolution ensures
excellent technical data.
The oscillator is powered by a separate
VEGA-signal conditioning instrument, a stabi-
lised power supply unit or a PLC (active
input). After adjustment, a standardised
current signal of 4 … 20 mA is available
which can be displayed (e.g. in PLC-sys-
tems) or further processed.
For versions are available for adjustment:
- adjustment module directly on VEGABAR
- adjustment module in external housing
(VEGADIS 10)
- via PC with adjustment software (see
manual “VEGA Visual Operating (VVO)“)
- in the control room on the signal condi-
tioning instrument
1.2 Self-monitoring
Important electronic components are
checked for their function, while internal pa-
rameters, such as sensor value, temperature
and operating voltage, are monitored to in-
crease reliability.
VEGABAR 20 with the ceramic CERTEC ® -
measuring cell offers the advantage of con-
tinuous self-monitoring. The measuring and
reference capacitances of the measuring cell
are in a defined ratio over the complete
measuring range. Any deviation from these
data is a reliable indicator for a malfunction of
the measuring cell.
If failures or malfunctions are detected during
these routines, a fault signal is triggered via
the 4 … 20 mA-output (current jump to
3,6 mA or 22 mA).