42
10 Diagnostics and servicing
VEGAPULS 11 • Two-wire 4 … 20 mA
58350-EN-221027
Liquids: Measurement error during emptying
Fault description
Cause
Rectification
Measured value remains un-
changed in the close range
during emptying
Level
time
0
False signal larger than the level echo
Level echo too small
Check measuring point: Antenna should
protrude out of the threaded mounting
socket, possible false echoes through
flange socket?
Remove contamination on the antenna
In case of interferences due to instal-
lations in the close range: Change
polarisation direction
After eliminating the false signals, the
false signal suppression must be de-
leted. Carry out a new false signal
suppression
Measured value jumps spo-
radically towards 100 %
during emptying
Level
time
0
Varying condensation or contamination
on the antenna
Carry out false signal suppression or in-
crease false signal suppression in the
close range by editing
With bulk solids, use radar sensor with
purging air connection
Bulk solids: Measurement error at constant level
Fault description
Cause
Rectification
Measured value shows a too
low or too high level
Leve
l
time
0
Min./max. adjustment not correct
Adapt min./max. adjustment
Incorrect linearization curve
Adapt linearization curve
Measured value jumps to-
wards 100 %
Level
time
0
Due to the process, the amplitude of the
product echo decreases
A false signal suppression was not car-
ried out
Carry out a false signal suppression
Amplitude or position of a false signal
has changed (e.g. condensation, build-
up); false signal suppression no longer
matches actual conditions
Determine the reason for the changed
false signals, carry out false signal sup-
pression, e.g. with condensation.
Bulk solids: Measurement error during filling
Fault description
Cause
Rectification
Measured value jumps to-
wards 0 % during filling
Level
time
0
The level echo cannot be distinguished
from the false signal at a false signal po-
sition (jumps to multiple echo)
Remove/reduce false signal: minimize
interfering installations by changing the
polarization direction
Chose a more suitable installation po-
sition
Transverse reflection from an extraction
funnel, amplitude of the transverse re-
flection larger than the level echo
Direct sensor to the opposite fun-
nel wall, avoid crossing with the filling
stream
