Siemens SITRANS L Operating Instructions Manual page 39

Diagnostics and troubleshooting
9.4 Treatment of measurement errors
Fault description
Measured value jumps
sporadically to 100 %
during filling
Measured value jumps to
≥ 100 % or 0 m distance
Fault description
Measured value remains
unchanged in the close
range during emptying
Measured value jumps
sporadically towards
100 % during emptying
32
Cause
Varying condensation or
contamination on the antenna
Level echo is no longer detected
in the close range due to foam
generation or false signals in the
close range. The transmitter goes
into overfill protection mode. The
max. level (0 m distance) as well
as the status message " Overfill
protection" are output.
Cause
False signal larger than the level
echo
Level echo too small
Varying condensation or
contamination on the antenna
Rectification
Carry out a auto false echo
suppression or increase auto
false echo suppression with
condensation/contamination in the
close range by editing
Check measuring point: Antenna
should protrude out of the threaded
mounting nozzle, possible false
echoes through flange nozzle?
Remove contamination on the
antenna
Rectification
Check measuring point: Antenna
should protrude out of the threaded
mounting nozzle, possible false
echoes through flange nozzle?
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
Operating Instructions, 12/2020, A5E49829013
SITRANS LR110