VEGA VEGAPULS 66 (≥ 2.0.0 - ≥ 4.0.0) standpipe ver. 4 … 20 mA_HART - two-wire - Manual (Page 43)

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9 Diagnosis, Asset Management and service
VEGAPULS 66 standpipe version • 4 … 20 mA/HART - two-wire
36523-EN-121011
9.4 Measurement error with constant level
Fault description Error pattern Cause Rectification
1. Measured value
shows a too low or too
high level
Level
time 0
– Min./max. adjustment not
correct
– Adapt min./max. adjustment
– Wrong linearization curve – Adapt linearization curve
– Installation in a bypass tube or
standpipe, hence running time
error (small measurement error
close to 100 %/large error close
to 0 %)
– Check parameter "Application"
with respect to vessel form,
adapt if necessary (bypass,
standpipe, diameter)
2. Measured value
jumps towards 100 % Level
time 0
– Due to the process, the ampli-
tude of the product echo sinks
– A false signal suppression was
not carried out
– Carry out false signal suppres-
sion
– Amplitude or position of a
false echo has changed (e.g.
condensation, buildup); false
signal suppression no longer
matches
– Determine the reason for the
changed false echo, carry out
false signal suppression, e.g.
with condensation
9.4 Measurement error during filling
Fault description Error pattern Cause Rectification
3. Measured value re-
mains in the area of the
bottom 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
4. 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
9.4 Measurement error during emptying
Fault description Error pattern Cause Rectification
5. Measured value re-
mains unchanged in
the close range during
emptying
Level
time 0
– False echo larger than the level
echo
– Level echo too small
– Remove false echoes in the
close range. Check: Antenna
must protrude out of the socket
– Remove contamination on the
antenna
– Minimize interfering instal-
lations in the close range by
changing the polarization
direction
– After removing the false ech-
oes, the false signal suppres-
sion must be deleted. Carry out
a new false signal suppression