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8 Diagnosis, asset management and service
LBR • Two-wire 4 … 20 mA/HART
62273-EN-200520
Error
Cause
Rectification
4 … 20 mA signal missing
Electrical connection faulty
Check connection, correct, if necessary
Voltage supply missing
Check cables for breaks; repair if nec-
essary
Operating voltage too low, load resist-
ance too high
Check, adapt if necessary
Current signal greater than
22 mA, less than 3.6 mA
Sensor electronics defective
Replace device or send in for repair de-
pending on device version
The tables below give typical examples of application-related meas-
urement errors.
The images in column "
Error description
" show the actual level as a
dashed line and the output level as a solid line.
1
2
Level
time
0
1 Real level
2 Level displayed by the sensor
Note:
If the output level is constant, the cause could also be the fault setting
of the current output to "
Hold value
".
If the level is too low, the reason could be a line resistance that is too
high
Measurement error with constant level
Fault description
Cause
Rectification
Measured value
shows a too low or
too high level
Level
time
0
Min./max. adjustment not correct
Adapt min./max. adjustment
Incorrect linearisation curve
Adapt linearisation curve
Measured val-
ue jumps towards
100 %
Level
time
0
Due to the process, the amplitude of the
product echo decreases
A false signal suppression was not car-
ried out
Carry out a false signal suppression
Amplitude or position of a false signal has
changed (e.g. condensation, buildup); false
signal suppression no longer matches ac-
tual conditions
Determine the reason for the changed false
signals, carry out false signal suppression,
e.g. with condensation
