Microlectra Dinel ULM-70, Instruction Manual

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8
© Dinel, s.r.o. ULM–70
• Scattering or attenuation of
the ultrasonic signal can result
if the surface level has been
moderately stirred or rippled
(by a mixer, coming liquid etc.).
It can result in reduction of the
measurement range or unreli-
able function of the level meter
(Fig. 10).
• Rotating mixer blades can cause
that the surface is stirred, which
results in false reflections of the
ultrasonic signal from the surface
level and unreliable operation of
the level meter (Fig. 13).(obr. 11).
For a rippled or swirling level,
you can use the directional
horn to eliminate scattering of
the ultrasonic signal.
• During filling, mixing and other processes, foam
can arise on the surface level of the measured liquid.
The foam considerably absorbs the ultrasonic sig -
nal which might cause malfunction of the level meter
(Fig. 9). For such cases, it is necessary to set up "SENSITIV -
ITY" mode to " high " or contact the manufacturer if need.
In case of a thin layer of foam, it is also possible to use
the directional horn for improving receipt of the reflec -
ted echo.
Fig. 9: Foam on the surface
Fig. 10: Moderately stirred
surface
Fig. 11: Intensely stirred surface
• If the level sensor is mounted to
bottlenecks and places with ba -
rriers, or near uneven walls or the
filling area, where the transmissi -
on signal could be distorted, we
recommend using a guide tube
(acoustic horn). The tube must
be made from a single material
with a smooth inner surface (see
image 12a, 12b ). The minimum
tube diameter must have the di -
mension "b" according to image
4 on page 5. After installing, you
must perform the procedure
"LEARNING". We recommend
consulting with the manufacture
on the construction of the guide
tube.
Fig. 12a: Short guide tube installation
ventilation
holes
sleeves for
mounting
Fig. 12b: Total guide tube
installation