User's Manual

Parameter reference
SITRANS LR250 (FOUNDATION FIELDBUS)
152 Operating Instructions, 01/2014, A5E32221411-AB
Hover Level (2.5.10.3.)
Defines how high the TVT (Time Varying Threshold) is placed above the noise floor of the echo
profile, as a percentage of the difference between the peak of the largest echo in the profile and
the noise floor. See
Auto False Echo Suppression (2.5.10.1)
for an illustration.
Values
Range: 0 to 100%
Default: 40%
When the device is located in the center of the vessel, the TVT hover level may be lowered to
increase the confidence level of the largest echo.
Shaper Mode (2.5.10.4.)
Enables/disables
TVT shaper
(2.5.11.)
Options
ON
*
OFF
TVT Shaper (2.5.11.)
Note
•
The range is –100 to +100 bits. With 2 bits per dB this gives a range of –50 to +50 dB.
•
Shaper Mode (2.5.10.4.)
must be turned
ON
in order for TVT shaper points to be
transferred.
Adjusts the TVT (Time Varying Threshold) at a specified range (breakpoint on the TVT). This
allows you to reshape the TVT to avoid unwanted echoes. There are 40 breakpoints arranged in
5 groups. (We recommend using SIMATIC PDM to access this feature.)
To use TVT shaper via LUI (local user interface):
1. Go to
Shaper Mode (2.5.10.4.)
and select
On
.
2. In TVT shaper, go to Breakpoint
1-9 (2.5.11.1.)
.
3. Open Breakpoint 1 and enter the TVT Offset value (between –50 and 50).
4. Go to the next Breakpoint and repeat step 3 until all desired breakpoint values have been
entered.