64
9 Diagnosis, asset management and service
VEGAPULS 64 • 4 … 20 mA/HART - two-wire
51141-EN-160815
Measurement error during filling
Fault description
Error pattern
Cause
Rectification
4. Measured value re-
mains unchanged
during filling
Level
time
0
– False signals in the close range
too big or level echo too small
– Strong foam or spout genera-
tion
– Max. adjustment not correct
– Eliminate false signals in the
close range
– Check measurement situation:
Antenna must protrude out of
the socket, installations
– Remove contamination on the
antenna
– In case of interferences due to
installations in the close range:
Change polarisation direction
– Create a new false signal sup-
pression
– Adapt max. adjustment
5. Measured value re-
mains in the bottom
section during filling
Level
time
0
– Echo from the tank bottom
larger than the level echo, for
example, with products with
ε
r
< 2.5 oil-based, solvents
– Check parameters Medium,
Vessel height and Floor form,
adapt if necessary
6. Measured value re-
mains momentarily
unchanged during fill-
ing and then jumps to
the correct level
Level
time
0
– Turbulence on the product
surface, quick filling
– Check parameters, change if
necessary, e.g. in dosing ves-
sel, reactor
7. Measured value
jumps towards 0 %
during filling
Level
time
0
– Amplitude of a multiple echo
(vessel top - product surface) is
larger than the level echo
– Check parameter "Application",
especially vessel top, type of
medium, dished bottom, high
dielectric constant, and adapt if
necessary
– The level echo cannot be distin-
guished from the false signal at
a false signal position (jumps to
multiple echo)
– In case of interferences due to
installations in the close range:
Change polarisation direction
– Chose a more suitable installa-
tion position
8. Measured value
jumps towards 100 %
during filling
Level
time
0
– Due to strong turbulence and
foam generation during filling,
the amplitude of the level echo
sinks. Measured value jumps to
false signal
– Carry out a false signal sup-
pression
9. Measured value
jumps sporadically to
100 % during filling
Level
time
0
– Varying condensation or con-
tamination on the antenna
– Carry out a false signal sup-
pression or increase false
signal suppression with con-
densation/contamination in the
close range by editing
10. Measured value
jumps to ≥ 100 % or
0 m distance
Leve
l
time
0
– Level echo is no longer
detected in the close range
due to foam generation or false
signals in the close range. The
sensor goes into overfill protec-
tion mode. The max. level (0 m
distance) as well as the status
message "Overfill protection"
are outputted.
– Check measuring site: Antenna
must protrude out of the socket
– Remove contamination on the
antenna
– Use a sensor with a more suit-
able antenna
