Tvt Setup (2.12.3.) - Siemens SITRANS L 7ML5400 Operating Instructions Manual

9.2.12.3

TVT Setup (2.12.3.)

Note
Default settings in the parameter tables are indicated with an asterisk (*) unless explicitly
stated.
Auto False Echo Suppression (2.12.3.1.)
Used together with Shaper Mode and Auto False Echo Suppression (Page 297) 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 (Page 297) for a more detailed explanation.
Note
• Make sure material level is below all known obstructions when Auto False Echo
Suppression is used to learn the echo profile. (An empty or almost empty vessel is
recommended.)
• Note the distance to material level when Auto False Echo learns the environment. Set
Auto False Echo Suppression Range to a shorter distance to avoid the material echo being
screened out.
• Set Auto False Echo Suppression and Auto False Echo Suppression Range during startup, if
possible.
• All other tuning and filter adjustments (such as Narrow Echo Filter (2.12.2.4.) (Page 225),
Reform Echo (2.12.2.3.) (Page 225), Hover Level (2.12.3.3.) (Page 228), and so on.)
should be completed prior to using Auto False Echo Suppression to ensure that the
learned profile is representative.
1. 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.
2. Subtract 0.5 m (20") from this distance, and use the resulting value.
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 Auto False Echo Suppression in LUT400
Communications manual
To set Auto False Echo Suppression via the local push buttons:
Options
3. Navigate to Setup (2.) (Page 172) > Signal Processing (2.12.) (Page 222) > TVT Setup
(2.12.3.) (Page 227) > Auto False Echo Suppression Range (2.12.3.2.) (Page 228), and enter
the value calculated in step 2).
SITRANS LUT400
Operating Instructions, 04/2021, A5E33329501-AG
.)
1
OFF
* ON
LEARN
Default TVT will be used.
'Learned' TVT will be used.
'Learn' the TVT.
Parameter reference (LUI)
9.2 Setup (2.)
227