Siemens SITRANS L Operating Instructions Manual page 45

Diagnostics and troubleshooting
9.5 Treatment of measurement errors
Fault description
Measured value jumps
sporadically towards
100 % during emptying
Fault description
Measured value shows a
too low or too high level
Measured value jumps
towards 100 %
Fault description
Measured value jumps
towards 0 % during filling
38
Cause
Varying condensation or
contamination on the antenna
Cause
Min./max. adjustment not correct
Incorrect linearization curve
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
Cause
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
Rectification
Remove contamination on the
antenna
In case of interferences due to
installations in the close range:
Change polarisation direction
After eliminating the false signals,
the auto false echo suppression
must be deleted. Carry out a new
auto false echo suppression
Carry out auto false echo
suppression or increase auto false
echo suppression in the close range
by editing
Rectification
Adapt min./max. adjustment
Adapt linearization curve
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.
Rectification
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
Operating Instructions, 10/2021, 62705-76-01
SITRANS LR100