Siemens SITRANS LG270 Operating Instructions Manual page 63

Measurement error with constant level
Fault description
1. Measured value
shows a too low or too
high level
2. Measured value
jumps towards 100 %
Measurement error during filling
Fault description
3. Measured value re-
mains in the area of the
bottom during filling
4. Measured value re-
mains momentarily
unchanged during fill-
ing and then jumps to
the correct level
5. Measured value
jumps sporadically to
100 % during filling
6. Measured value
jumps to ≥ 100 % or
0 m distance
PBD-51041064
Error pattern Cause
•
Min./max. adjustment not
correct
•
Incorrect linearisation curve
•
0 time
Running time error (small meas-
urement error close to 100 %/
serious error close to 0 %)
•
Due to the process, the
amplitude of the product echo
decreases
•
A false signal suppression was
0 time not carried out
•
Amplitude or position of a
false signal has changed (e.g.
buildup); false signal suppres-
sion no longer matches
Error pattern Cause
•
Echo from the probe end larger
than the product echo, for exam-
ple, with products with ε
oil-based, solvents, etc.
0
time
•
Turbulence on the product
surface, quick filling
0
time
•
Changing condensation or
contamination on the probe
0
time
•
Level echo is no longer detected
in the close range due to false
signals in the close range. The
sensor goes into overfill protec-
tion mode. The max. level (0 m
0 time
distance) as well as the status
message "Overfill protection"
are outputted.
SITRANS LG270 - Operating Instructions
Rectification
•
Adapt min./max. adjustment
•
Adapt linearisation curve
•
Repeat setup
•
Carry out a false signal suppres-
sion
•
Determine the reason for the
changed false signals, carry out
false signal suppression, e.g.
with buildup
Rectification
•
Check parameter "Medium"
and "Vessel height", adapt if
< 2.5 necessary
r
•
Check parameters, change if
necessary, e.g. in dosing vessel,
reactor
•
Carry out a false signal suppres-
sion
•
Eliminate false signals in the
close range
•
Check installation conditions
•
If possible, switch off the func-
tion "Overfill protection"
63