3 mounting and installation, 1 general installation instructions, Measuring range – VEGA VEGAPULS 51K…54K 4 … 20 mA; HART compact sensor User Manual

Page 11: False echoes

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VEGAPULS 51K … 54K

11

21750-EN-031222

Mounting and installation

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

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
(VEGAPULS 51, 52). The measuring range is
0 … 20 m. When measuring in a surge or
bypass tube (pipe antenna), the max. meas-
uring distance is reduced.

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 50 sensors are suitable for
measurement of solids only under certain
conditions.

Profiles with flat interfering surfaces cause large
false signals

Round profiles diffuse radar signals

Cover smooth interfering surfaces with deflectors

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.

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 taking a direct path back to the
radar sensor. The signals are then so low-
energy and diffuse that they can be filtered
out by the sensor.

empty

Meas. range

max. meas. distance 20 m

Reference plane

full

4 m

16 m

max.

max.

max.

max. filling

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