VEGA VEGAPULS 45 4 … 20 mA; HART compact sensor - Manual (Page 12)

12 VEGAPULS 42, 44 and 45 – 4 … 20 mA
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. For meas-
urements 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.
Profiles with smooth 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 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.
full
Meas. range
max. meas. distance 20 m (type 45: 4 m)
Reference plane empty
max.
max.
max. filling
max.
min. min.