Diagnostics and troubleshooting
9.5 Treatment of measurement errors
Fault description
Cause
Rectification
false echo suppression no longer
matches actual conditions
auto false echo suppression, e.g.
with condensation.
Fault description
Cause
Rectification
The level echo cannot be
distinguished from the false signal
at a false signal position (jumps to
multiple echo)
Remove/reduce false signal:
minimize interfering installations by
changing the polarization direction
Chose a more suitable installation
position
Measured value jumps
towards 0 % during filling
Transverse reflection from an
extraction funnel, amplitude of the
transverse reflection larger than the
level echo
Direct transmitter to the opposite
funnel wall, avoid crossing with the
filling stream
Various echoes from an uneven
medium surface, e.g. a material
cone
Check parameter "Material Type"
and adapt, if necessary
Optimize installation position and
transmitter orientation
Measured value fluctuates
around 10 … 20 %
Reflections from the medium
surface via the vessel wall
(deflection)
Select a more suitable installation
position, optimize transmitter
orientation, e.g. with a swivelling
holder
Measured value jumps
sporadically to 100 %
during filling
Changing condensation or
contamination on the antenna
Carry out a auto false echo
suppression or increase auto
false echo suppression with
condensation/contamination in the
close range by editing
Fault description
Cause
Rectification
Measured value remains
unchanged in the close
range during emptying
False signal greater than level echo
or level echo too small
Eliminate false signals in the close
range. Check: Antenna must
protrude out of the nozzle
Remove contamination on the
antenna
Minimize interfering installations
in the close range by changing the
polarization direction
SITRANS LR140
Operating Instructions, 08/2020,
A5E50352144
37
