VEGA VEGAPULS 45 VBUS - Manual (Page 4)

4 VEGAPULS 42, 44 and 45 – VBUS
1 ns
278 ns
Pulse sequence
Product description
emission - reflection - reception
Meas.
distance
1 Product description
VEGAPULS series 40 sensors are a newly
developed generation of very compact, small
radar sensors for high resolution and accu-
racy. They are characterised by special
focusing features for level measurement in
narrow space applications. With modest
space requirements they were developed for
measuring distances of 0 … 4 m/10 m/20 m
and for standard applications such as stor-
age vessels and buffer tanks as well as for
process tanks. With small housing dimen-
sions and process fittings, the compact sen-
sors monitor your levels at reasonable cost.
With the integrated display they enable high
precision level measurements and due to
their advantages, radar sensors have
increasingly become the standard solution
for many applications, even for those where it
was previously unthinkable due to high
costs.
VEGAPULS 40 radar sensors utilise two-wire
technology perfectly. The supply voltage and
the output signal are transmitted via one two-
wire cable. They provide a digital output
signal (VBUS or Profibus) or an analogue
4 … 20 mA signal as output or measuring
signal.
This operating instruction manual relates
to VEGAPULS 42, 44 and 45 sensors with
digital VBUS output signal (VEGA-Bus).
1.1 Function
Ra dio d etecting a nd r anging: Radar.
VEGAPULS radar sensors are used for non-
contact, continuous distance measurement.
The measured distance corresponds to a
filling height and is outputted as level.
Measuring principle:
emission – reflection – reception
Tiny 26 GHz radar signals are emitted from
the antenna of the radar sensor as short
pulses. The radar impulses reflected by the
sensor environment and the product are
received by the antenna as radar echoes.
The running period of the radar impulses
from emission to reception is proportional to
the distance and hence to the level.
The radar impulses are emitted by the an-
tenna system as pulse packages with a
pulse duration of 1 ns and pulse intervals of
278 ns; this corresponds to a pulse package
frequency of 3.6 MHz. In the impulse inter-
vals, the antenna system operates as re-
ceiver. Signal running periods of less than
one billionth of a second must be processed
and the echo image evaluated in a fraction of
a second.