Burkert 8136 Mode D'emploi page 54

Measurement error with constant level
Fault description
1. Measured value
shows a too low or too
high level
2. Measured value
jumps towards 0 %
3. Measured value
jumps towards 100 %
Measurement error during filling
Fault description
4. Measured value re-
mains unchanged
during filling
5. Measured value re-
mains in the bottom
section during filling
6. Measured value re-
mains momentarily
unchanged during fill-
ing and then jumps to
the correct level
LEVEL TRANSMITTER 8136 • 4 ... 20 mA/HART - two-wire
Error pattern Cause
– Min./max. adjustment not
correct
– Incorrect linearization curve
0
time
– Installation in a bypass tube or
standpipe, hence running time
error (small measurement error
close to 100 %/large error close
to 0 %)
– Multiple echo (vessel top,
product surface) with amplitude
higher than the level echo
0
time
– Due to the process, the ampli-
tude of the level echo sinks
– A false signal suppression was
not carried out
0
time
– Amplitude or position of a false
signal has changed (e.g. con-
densation, buildup); false signal
suppression no longer matches
actual conditions
Error pattern Cause
– False signals in the close range
too big or level echo too small
– Strong foam or spout genera-
tion
0 time
– Max. adjustment not correct
– Echo from the tank bottom
larger than the level echo, for
example, with products with
ε < 2.5 oil-based, solvents
r
0
time
– Turbulence on the product
surface, quick filling
0
time
9 Diagnosis, asset management and service
Rectification
– Adapt min./max. adjustment
– Adapt linearization curve
– Check parameter "Application"
with respect to vessel form,
adapt if necessary (bypass,
standpipe, diameter)
– Check parameter "Application",
especially vessel top, type of
medium, dished bottom, high
dielectric constant, and adapt if
necessary
– Carry out a false signal sup-
pression
– Determine the reason for the
changed false signals, carry out
false signal suppression, e.g.
with condensation
Rectification
– 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
– Check parameters Medium,
Vessel height and Floor form,
adapt if necessary
– Check parameters, change if
necessary, e.g. in dosing ves-
sel, reactor
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