VEGA VEGAPULS 51K…54K Profibus PA - Manual (Page 11)

VEGAPULS 51P … 54P 11
24890-EN-041227
Types and versions
2 Types and versions
VEGAPULS series 50 sensors are a newly
developed generation of extremely compact
radar sensors. With very modest space
requirements, they were developed for
measuring distances of 0 … 20 m and for
standard applications such as storage ves-
sels, reservoirs and buffer tanks as well as
process tanks.
Due to their small housing dimensions and
process fittings, the compact sensors are a
very cost-effective solution for your level
measurement applications. With their inte-
grated display and remarkable sensor intelli-
gence, they bring the advantage of radar
level measurement to applications where
previously, due to high costs, the advan-
tages of non-contact measurement had to be
foregone.
VEGAPULS 50 radar sensors are perfectly
suited to two-wire technology. The supply
voltage and the output signal are transmitted
via one two-wire cable. As output or measur-
ing signal, the instruments produce a digital
output signal (Profibus PA).
2.1 Antennas
The antenna is the eye of the radar sensor.
The shape of the antenna, however, doesn’t
give a casual observer the slightest clue on
how carefully the antenna geometry must be
adapted to the physical properties of electro-
magnetic waves. The geometrical form deter-
mines focal properties and sensitivity - the
same way it determines the sensitivity of a
unidirectional microphone.
Four antenna systems were developed for
different applications and process require-
ments. Beside different focusing characteris-
tics, each one has special chemical and
physical characteristics.
Rod antennas
Rod antennas with the best
chemical resistance require
the smallest flange diameters
(DN 50). The antenna rod and
the wetted flange parts are
made of PTFE, PP or PPS to
ensure that they are easily
cleanable and insensitive to
condensation. It is suitable for
pressures up to 16 bar and
temperatures up to 150°C.
Horn antenna
Horn antennas are well suited
for most applications. They
focus the radar signals ex-
ceptionally well. Manufactured
of 1.4571 (StSt) or Hastelloy
C22, they are very rugged,
and physically as well as
chemically resistant. They are
suitable for pressures up to
40 bar and for product tem-
peratures up to 150°C.
Pipe antenna
Pipe antennas on surge or
bypass tubes only form a
complete antenna system in
conjunction with a measuring
tube (which can also have a
bend). Pipe antennas are
especially suitable for prod-
ucts with strong flow or turbu-
lence or products with low
dielectric constant.