Siemens sitrans LU01 - Manual (Page 106)

Page 100 SITRANS LU01 – INSTRUCTION MANUAL 7ML19985BE02
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Measurement Difficulties
If a measurement difficulty occurs for greater than the Failsafe Timer (P070) setting, LOE
is flashed alternately with the Reading display. Under certain conditions, a measurement
difficulty may cause the SITRANS LU01 to lock on to a false echo and report a fixed or
wrong reading.
Flashing LOE Display
If LOE is displayed, ensure that the:
1. Material (object) surface monitored is within the maximum range of the transducer.
2. Transducer (P004) value matches the transducer used.
3. Transducer is located and aimed properly.
(See the Transducer manual for maximum range, mounting and rough aiming
instructions.)
For optimum performance, adjust the transducer aiming while monitoring the Echo
Confidence (P805) for various material levels over the measurement range. When
complete, set the transducer aiming at the best angle for all levels.
To display Echo Confidence in the RUN mode:
Press and hold for 4 seconds (Failsafe Time Left changes to the Short : Long
Confidence display).
To display Echo Confidence in PROGRAM mode, access the Echo Confidence (P805)
parameter.
To update the value displayed after each aiming adjustment...
Press (5 times or more to verify stability)
If the condition persists (despite optimum aiming), optimize transducer performance. (See
Enhancement Parameters Short Shot Frequency, P840 and Long Shot Frequency, P841).
Increase the Failsafe Timer (P070) value, if failsafe operation will not be compromised by
the larger value.
If LOE is displayed only when a sloped bottom vessel is near Empty, the echo is probably
being reflected away from the transducer. Install an empty target plate in the bottom of
the vessel. When exposed (not covered by material), the target plate provides the
reflective surface representative of an empty vessel.
Install a longer range transducer, enter the new Empty (P006) distance, and (if necessary)
optimize aiming and frequency again.
If a longer range transducer is not available, connect an oscilloscope to the SITRANS
LU01, (see Enhancement Parameters Scope Displays, P810).