WRONG READING
If the Reading is erratic, or jumps to some incorrect value periodically, ensure the:
1. Material ( object ) surface monitored, is not beyond the transducers maximum range.
2. Material is not falling in the transducer sound beam.
3. Material ( P002 ) value matches the material monitored.
4. Measurement Response ( P003 ) is not set too fast.
5. Transducer ( P004 ) type entered matches the transducer used.
If the periodic incorrect value is always the same, see Fixed Reading. If the incorrect value seems to be
random, ensure the material surface to transducer distance is less than the Empty value entered plus 20%. If
the material / object monitored is outside this distance, increase Range Extension (P801) as required.
If the material monitored is a liquid, check for splashing in the vessel. Increase Measurement Response as
required to stabilize the Reading, or install a stilling well ( contact Milltronics or your local distributor ).
Access the Noise ( P807 ) parameter. If the peak value jumps wildly, verify the transducer cables are run in
grounded metal conduit; separate from other wiring, and transducer cable shields are connected to the XPL+
shield terminals and not to ground elsewhere.
If the XPL+ is mounted in close proximity to (or transducer cables run near those of) another ultrasonic level
monitor, see Level System Sync (P726).
Temporarily disable nearby SCR control drives, high voltage or current contactors. If the condition disappears,
move the XPL+ to another location.
Set Echo Lock (P711) to "max verification" ( response to material level changes may be slowed somewhat ).
Increase the Confidence Threshold ( small amounts at a time ) while observing the results. If performance is
not improved return the Confidence Threshold to the preset value.
Connect an oscilloscope to the XPL+, ( see ENHANCEMENT PARAMETERS Scope Displays, P810 ).
While monitoring the Echo Marker, select the Algorithm (P820) best suited to the material / conditions.
If the "Area" algorithm is used and narrow noise spikes are evident on the (long shot) Echo Profile, turn the
Spike Filter ( P821 ) on and / or widen the Narrow Echo Filter ( P822 ). Also, if the true echo has jagged
peaks, use Reform Echo ( P823 ).
If multiple echoes appear on the Echo Profile, typical of a flat material profile ( especially if the vessel top is
domed ), use the "first" Algorithm.
If the Echo Profile repeatedly switches from short to long, adjust the Short Shot Range ( P852 ) to stabilize
the "shot" mode used for the echo evaluation. Also, adjust the Short Shot Bias to increase ( or decrease ) the
amount of preference given to short shot echoes over long shot echoes.
Should a stable measurement still not be attainable, contact Milltronics or your local distributor.
ENHANCEMENT PARAMETERS
PL-532 102
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