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, verify 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. Decrease Measurement
Response (P003) 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 cable shields are
connected to the DPL+ shield terminals and not to ground elsewhere.
If the DPL+ 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 DPL+ 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 DPL+, (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-508 100
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