VEGA VEGAPULS 45 4 … 20 mA; HART compact sensor - Manual (Page 4)

4 VEGAPULS 42, 44 and 45 – 4 … 20 mA
Product description
emission - reflection - reception
Meas.
distance
1 Product description
VEGAPULS series 40 sensors are a newly
developed generation of extremely compact,
small radar sensors for accurate, high-reso-
lution measurement. They are characterised
by very good focussing properties for appli-
cations in narrow spaces. With very modest
space requirements, they were developed
for measuring distances of 0 … 4 m/10 m/
20 m and are the right choice for standard
applications such as storage vessels, reser-
voirs and buffer tanks as well as process
tanks.
Due to small housing dimensions and proc-
ess fittings, the compact sensors are an
unobstrusive, and most of all, very cost-
effective solution for your level measurement
applications. With the integrated display, they
enable high precision level measurements
and make accessible the advantages of non-
contact measurement in applications where,
due to high cost, they previously couldn’t be
put into effect.
VEGAPULS 40 radar sensors are perfectly
suited to two-wire technology. The supply
voltage and the output signal are transmitted
via one two-wire cable. The instruments pro-
duce an analogue 4 … 20 mA output signal
as output, i.e. measuring signal.
1.1 Function
Ra dio d etecting a nd r anging: Radar.
VEGAPULS radar sensors are used for non-
contact and continuous distance measure-
ment. The measured distance corresponds
to a filling height and is outputted as level.
Measuring principle:
emission – reflection – reception
Extremely small 26 GHz radar signals are
emitted from the antenna of the radar sensor
as short pulses. The radar pulses reflected
by the sensor environment and the product
are received by the antenna as radar ech-
oes. The running period of the radar pulses
from emission to reception is proportional to
the distance and hence to the level.
The radar pulses are emitted by the antenna
system as pulse packets with a pulse dura-
tion of 1 ns and pulse intervals of 278 ns; this
corresponds to a pulse package frequency
of 3.6 MHz. In the pulse intervals, the antenna
system operates as a receiver. Signal run-
ning periods of less than one billionth of a
second must be processed and the echo
image evaluated in a fraction of a second.
1 ns
278 ns
Pulse sequence