3 mounting and installation, 1 general installation instructions, Measuring range – VEGA VEGAPULS 45 Profibus PA User Manual

Page 15: False echoes

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VEGAPULS 42, 44 and 45 – Profibus PA

15

24908-EN-041227

Mounting and installation

3 Mounting and installation

3.1 General installation instructions

Measuring range

The reference plane for the measuring range
of the sensor is the lower edge of the flange
or the seal shoulder of the thread. For meas-
urement in surge or bypass tubes with
VEGAPULS 45 the max. distance depends
on the tube length.

Keep in mind that in measuring environments
where the medium can reach the sensor
flange, buildup may form on the antenna and
later cause measurement errors.

Note: The series 40 sensors are suitable for
measurement of solids only under certain
conditions.

False echoes

Flat obstructions and struts cause strong
false echoes. They reflect the radar signal
with high energy density.

Interfering surfaces with rounded profiles
scatter the radar signals into the surrounding
space more diffusely and thus generate false
echoes with a lower energy density. Hence,
those reflections are less critical than those
from a flat surface.

Profiles with smooth interfering surfaces cause large
false signals

Round profiles diffuse radar signals

Cover flat surfaces with deflectors

If flat obstructions in the range of the radar
signals cannot be avoided, we recommend
diverting the interfering signals with a deflec-
tor. The deflector prevents the interfering
signals from being directly received by the
radar sensor. The signals are then so low-
energy and diffuse that they can be filtered
out by the sensor.

Measuring range (operating range) and max. measuring distance
Note: Use of the sensors for applications with solids is limited.

full

Meas. range

max. meas. distance 20 m (type 45: 4 m)

Reference plane

empty

max.

max.

max. filling

min.

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