VEGA VEGACAP 82-98 - Manual (Page 4)

4 VEGACAP
Product description
1 Product description
1.1 Function and configuration
The compact capacitive level switches VE-
GACAP detect the level of virtually any me-
dium regardless of whether in liquid, powder,
paste or granule form. This applies also to
adhesive products.
Depending on the chosen adjustment,
VEGACAP can detect if the medium exceeds
or fails to reach a defined level.
Sensor, processing electronics and power
supply form one unit in VEGACAP. The
modular construction ensures adaption to
virtually any application. Beside rod, cable,
high temperature and plate electrodes, there
are also three electronics versions available
(non-contact switch, relay or transistor output
NPN/PNP).
VEGACAP 27, 35 and 98 combine all these
positive features with the advantage that an
adjustment with medium is no longer neces-
sary. This is made possible by the oscillator
CAP E31 R and the patented mechanical
configuration of the electrode.
Application
The area of application for VEGACAP is
mainly in the detection of max. and min. levels
in vessels. A switching command can be
triggered either when the electrode is im-
mersed or exposed. VEGACAP can be
mounted laterally, from the top or from the
bottom.
Partly insulated
The electrode is insulated over a defined
length. The measurement is made only in the
uninsulated zone.
Fully insulated
The electrode is insulated along the entire
length; on cable electrodes also the gravity
weight can be fully insulated.
Measuring principle
Electrode, medium and vessel wall form an
electrical capacitor.
The capacitance of the capacitor is generally
influenced by three factors:
- distance of the electrode plates (a)
- size of the electrode plates (b)
- type of dielectric between the electrodes
(c)
The electrode and the vessel wall are the
capacitor plates. The medium is the dielec-
tric. Due to the higher dielectric constant (DK-
value) of the medium compared with air, the
capacitance of the capacitor increases as the
electrode is gradually immersed.
The capacitance change is converted by the
oscillator into a switching command.
a
b
c