MEASUREMENT DIFFICULTIES
If the Failsafe Timer (P070) expires due to a measurement difficulty, "LOE" flashes
alternately with the Reading. In rare cases, the HYDRO+ may "lock on" to a false
echo and report a fixed or wrong Reading.
FLASHING "LOE" DISPLAY
If "LOE" is displayed, ensure the:
1. Surface monitored is within the transducer maximum range.
2. Transducer (P004) value matches the transducer used.
3. Transducer is located and aimed properly.
See the Transducer instructions for range, mounting, and rough aiming details.
For optimum performance, adjust transducer aiming to provide the best Echo
Confidence (P805) for all material levels within the measurement range.
To display Echo Confidence in the RUN mode...
and hold for 4 seconds (Failsafe Time Left changes to the Short:Long
Confidence display).
To display Echo Confidence in the program mode, access the Echo Confidence
(P805) parameter. To update the value displayed after each aiming adjustment...
(5 times or more to verify stability)
If the condition persists (despite optimum aiming), optimize transducer performance.
Adjust Short Shot Frequency, (P842) and Long Shot Frequency (P843) for maximum
Echo Confidence (P805).
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, install an
"target plate" in the bottom of the vessel. When exposed, 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, (see Scope Displays, P810).
If an echo is observed (from the material/object surface), reduce the Confidence
Threshold (P804) while taking new measurements (in the RUN or program mode).
If the surface cannot be detected during high vessel activity, set up Failsafe Operation
to "anticipate" the material level change. This operation is reliable, as long as when
the foam (or dust) settles a valid echo can be received. See APPLICATIONS
Failsafe Operation.
APPLICATIONS
PL-507 158
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