Siemens SITRANS LG260 Operating Instructions Manual page 50

Fault description
Measured value
fluctuates around
10 ... 20 %
0 time
Treatment of measure-
ment errors
Measurement error with constant level
Fault description
Measured value shows a
too low or too high level
0
time
50
Cause
Various echoes from an uneven product
surface, e.g. an extraction funnel
Reflections from the product surface via the
vessel wall (deflection)
The below tables show typical examples for application-relevant
measurement errors. There are two measurement errors:
•
Constant level
•
Filling
•
Emptying
The images in column "Error pattern" show the real level as a broken
line and the level displayed by the sensor as a continuous line.
Fig. 20: The broken line 1 shows the real level, the continuous line 2 shows the
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
Cause
Min./max. adjustment not correct
Incorrect linearisation curve
Running time error (small measurement
error close to 100 %/serious error close
to 0 %)
SITRANS LG260 - Operating Instructions
Rectification
Check parameter "Material Type" and
adapt, if necessary
Optimize installation position and sensor
orientation
0
Rectification
Adapt min./max. adjustment
Adapt linearisation curve
Repeat setup
1
2
time
PBD-51041061