Siemens SITRANS L Operating Instructions Manual page 50

Measured value jumps
towards 100 %
Measured value jumps
towards 0 % during filling
Measured value fluctuates
around 10 ... 20 %
Measured value jumps
sporadically to 100 %
during filling
SITRANS LR120, HART
Operating Instructions, 10/2023, A5E49829026
Fault description
Due to the process, the amplitude
of the product echo decreases
A auto false echo suppression was
not carried out
Amplitude or position of a
false signal has changed (e.g.
condensation, buildup); auto
false echo suppression no longer
matches actual conditions
Fault description
The level echo cannot be
distinguished from the false signal
at a false signal position (jumps to
multiple echo)
Transverse reflection from an
extraction funnel, amplitude of the
transverse reflection larger than the
level echo
Various echoes from an uneven
medium surface, e.g. a material
cone
Reflections from the medium
surface via the vessel wall
(deflection)
Changing condensation or
contamination on the antenna
Diagnostics and troubleshooting
10.5 Treatment of measurement errors
Cause
Carry out a auto false echo
suppression
Determine the reason for the
changed false signals, carry out
auto false echo suppression, e.g.
with condensation.
Cause
Remove/reduce false signal:
minimize interfering installations by
changing the polarization direction
Chose a more suitable installation
position
Direct transmitter to the opposite
funnel wall, avoid crossing with the
filling stream
Check parameter "Material Type"
and adapt, if necessary
Optimize installation position and
transmitter orientation
Select a more suitable installation
position, optimize transmitter
orientation, e.g. with a swivelling
holder
Carry out a auto false echo
suppression or increase auto
false echo suppression with
condensation/contamination in the
close range by editing
Rectification
Rectification
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