WRONG READING
If the Reading is erratic, or jumps to some incorrect value periodically, ensure the:
1. Surface monitored, is not beyond the transducers maximum range.
2. Material is not falling into the transducer acoustic 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 a periodic wrong Reading is always the same value, see Fixed Reading. If the
wrong Reading is 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. Enter a lower
Measurement Response (P003) value to stabilize the Reading, or install a stilling well.
(Contact Milltronics or your local distributor).
If the Noise (P807) peak value jumps wildly, or average value is greater than +5 dB
verify the transducer cable shields are connected to the HYDRO+ shield terminals
and not to ground elsewhere.
If the HYDRO+ 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 HYDRO+ 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 HYDRO+, (see 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.
PARAMETERS
PL-507 160
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