Set The Sitrans Lut400 To Ignore The Bad Echo; Wrong Reading; Types Of Wrong Readings; Liquid Splashing - Siemens SITRANS LUT400 Operating Instructions Manual

Set the SITRANS LUT400 to Ignore the Bad Echo

If the preceding remedies have not fixed the problem, the false echo has to be ignored.
If the Echo is Close to the Transducer
If there is a static, incorrect, high level reading from the SITRANS LUT400 there is
probably something reflecting a strong echo back to the transducer. If the material level
never reaches that point extend the
obstruction.
Adjust the TVT to Ignore the Echo
2.12.3.1. Auto False Echo Suppression
Use
TVT Shaper
to manually shape around false echoes.

Wrong Reading

If the Reading is erratic, or jumps to some incorrect value periodically, ensure the:
1. Surface monitored is not beyond the SITRANS LUT400's programmed range or the
transducer's maximum range.
2. Material is not falling into the transducer's acoustic beam.
3. Material is not inside the blanking distance (near range) of the transducer.

Types of Wrong Readings

If a periodic wrong Reading is always the same value, see "Fixed Reading" on page 245
If the wrong Reading is random, ensure the distance from the transducer to the material
surface is less than
the measurement range programmed in the device). If the material/object monitored is
outside this range, increase
OCM applications using weirs.

Liquid Splashing

If the material monitored is a liquid, check for splashing in the vessel. Enter a lower
Response Rate
value (see page 42) to stabilize the Reading, or install a stilling well.
(Contact Siemens representative.)

Adjust the Echo Algorithm

Use SIMATIC PDM to view echo profiles and make adjustments to the
2.12.2. 1 . Algorithm
parameter. See
If the "TRACKER" algorithm is used and narrow noise spikes are evident on the Echo
Profile, widen the
2. 1 2.2.3. Reform Echo
If multiple echoes appear on the Echo Profile, typical of a flat material profile (especially if
the vessel top is domed), use the "TF " (True First) algorithm.
Should a stable measurement still not be attainable, contact Siemens representative.
Page 246 SITRANS LUT400 (HART) – OPERATING INSTRUCTIONS
2.2.4. Near Range
2.2.5. Far Range
value plus one meter (i.e. ensure you are still within
2.2.5. Far Range
on page 182 for details.
2. 1 2.2.4. Narrow Echo Filter
.
to a distance to just past the
. If this does not correct the problem, use
as required. This error is most common in
. Also, if the true echo has jagged peaks, use
2.12.4.
.
Algorithm
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