38
10 Diagnostics and servicing
VEGAPULS C 11 • Two-wire 4 … 20 mA
58340-EN-200806
Liquids: Measurement error during emptying
Fault description Cause Rectication
Measured value remains un-
changed in the close range
during emptying
Level
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
angesocket?
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
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 Rectication
Measured value shows a too
low or too high level
Level
0
Min./max. adjustment not correct Adapt min./max. adjustment
Incorrect linearization curve Adapt linearization curve
Measured value jumps to-
wards 100 %
Level
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.
Bulksolids:Measurementerrorduringlling
Fault description Cause Rectication
Measured value jumps to-
wards0%duringlling
Level
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
Transversereectionfromanextraction
funnel, amplitude of the transverse re-
ectionlargerthanthelevelecho
Direct sensor to the opposite fun-
nelwall,avoidcrossingwiththelling
stream