Vega VEGAPULS 11 - Page 41

41
10 Diagnostics and servicing
VEGAPULS 11 • Two-wire 4 … 20 mA
58350-EN-200806
Fault description Cause Rectication
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lling
Fault description Cause Rectication
Measured value jumps to-
wards0%duringlling
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reectionfromanextraction
funnel, amplitude of the transverse re-
ectionlargerthanthelevelecho
Direct sensor to the opposite fun-
nelwall,avoidcrossingwiththelling
stream
Measuredvalueuctuates
around 10 … 20 %
Level
time
0
Various echoes from an uneven medi-
um surface, e.g. a material cone
Check parameter "Material Type" and
adapt, if necessary
Optimize installation position and sen-
sor orientation
Reectionsfromthemediumsurface
viathevesselwall(deection)
Select a more suitable installation po-
sition, optimize sensor orientation, e.g.
with a swivelling holder
Measured value jumps spo-
radically to 100 % during
lling
Level
time
0
Changing condensation or contamina-
tion on the antenna
Carry out a false signal suppression
or increase false signal suppression
with condensation/contamination in the
close range by editing
Bulk solids: Measurement error during emptying
Fault description Cause Rectication
Measured value remains un-
changed in the close range
during emptying
Level
time
0
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 polariza-
tion direction
After eliminating the false signals, the
false signal suppression must be de-
leted. Carry out a new false signal
suppression