Siemens SITRANS LUT400 Operating Instructions Manual page 192

The submergence condition remains in effect until the transducer is no
longer submerged. A valid echo must then be detected before the LOE
Timer expires or the device will enter fail-safe condition (see
Safe
2.12.3. TVT Setup
Note: Default settings in the parameter tables are indicated with an asterisk (*)
unless explicitly stated.
2.12.3.1. Auto False Echo Suppression
Used together with Auto False Echo Suppression Range (2.12.3.2.) to
screen out false echoes in a vessel with known obstructions. A 'learned
TVT' (time varying threshold) replaces the default TVT over a specified
range. See Shaper Mode and Auto False Echo Suppression on page 260
for a more detailed explanation.
Notes:
• Make sure material level is below all known obstructions when Auto
• Note the distance to material level when Auto False Echo learns the
• Set Auto False Echo Suppression and Auto False Echo Suppression
• All other tuning and filter adjustments (such as
a)
b)
To set Auto False Echo Suppression via SIMATIC PDM:
Open the menu Device – Echo Profile Utilities and click on the tab Auto
False Echo Suppression.
(For more detailed instructions see
Communications manual
1.
Communications for SITRANS LUT400 (HART) Manual (7ML19985NE01)
Page 184 SITRANS LUT400 (HART) – OPERATING INSTRUCTIONS
).
False Echo Suppression is used to learn the echo profile. (An empty or
almost empty vessel is recommended.)
environment. Set Auto False Echo Suppression Range to a shorter
distance to avoid the material echo being screened out.
Range during startup, if possible.
Filter 2.12.2.3. Reform Echo
,
completed prior to using Auto False Echo Suppression to ensure that
the learned profile is representative.
Determine Auto False Echo Suppression Range. Measure the actual
distance from the sensor reference point to the material surface
using a rope or tape measure.
Subtract 0.5 m (20") from this distance, and use the resulting value.
1
.)
2.12.2.4. Narrow Echo
2.12.3.3. Hover Level
, , etc.) should be
Auto False Echo Suppression
2.4. Fail-
in LUT400
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