VEGA VEGAPULS 66 (≥ 2.0.0 - ≥ 4.0.0) Foundation Fieldbus - Manual (Page 54)

54
9 Diagnosis, Asset Management and service
VEGAPULS 66 • Foundation Fieldbus
36522-EN-121011
9.4 Measurement error during filling
Fault description Error pattern Cause Rectification
4. Measured value re-
mains unchanged
during filling
Level
time 0
– False echoes in the close range
too big or product echo too
small
– Strong foam or spout genera-
tion
– Max. adjustment not correct
– Eliminate false echoes in the
close range
– Check measurement situation:
Antenna must protrude out of
the socket, installations
– Remove contamination on the
antenna
– Minimize interfering instal-
lations in the close range by
changing the polarization
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 product echo,
for example, with products with
ε
r
< 2.5 oil-based, solvents
– Check application 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 application parameters,
change if necessary, e.g. in
dosing vessel, 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, product
type, dished end, high dielectric
figure, adapt if necessary
– The level echo cannot be distin-
guished from the false echo at
a false echo position (jumps to
multiple echo)
– Remove/reduce false echo:
minimize interfering installa-
tions by changing the polariza-
tion 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 product
echo sinks. Measured value
jumps to the false echo
– Carry out false signal suppres-
sion
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
echoes 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