Siemens SITRANS LR250 Operating Instructions Manual page 90

Remote operation
7.1 Operating via SIMATIC PDM
If you have a vessel with known obstructions, use Auto False Echo Suppression to prevent false
echo detection. This feature can also be used if the device displays a false high level, or the
reading is fluctuating between the correct level and a false high level.
The device learns the echo profile over the whole measurement range and the TVT is shaped
around all echoes present at that moment. See Auto False Echo Suppression (Page 236) for a
more detailed explanation.
The learned TVT will be applied over a specified range. The default TVT is applied over the
remainder of the measurement range.
1. Make sure the material level is below all known obstructions.
2. 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.
3. Open the menu Device – Echo Profile Utilities and click on the tab Auto False Echo
Suppression.
4. Make sure Auto False Echo Suppression Range is On.
5. Enter the value for Auto False Echo Suppression Range.
6. Click Learn. The message appears: 'This will learn a new echo profile. Once done it cannot
be undone'. Click OK.
7. Once Auto TVT is complete click Transfer to Device. To exit click Close. Auto TVT is enabled
and the learned TVT will be used.
8. To turn Auto False Echo Suppression off or on, reopen the Auto False Echo Suppression
window, change the Auto False Echo Suppression to Off or On, click on Transfer to Device.
88
SITRANS LR250 (PROFIBUS PA)
Operating Instructions, 08/2014, A5E32221386-AC