Emerson Rosemount 5408 Reference Manual page 269

Reference Manual
00809-0100-4408
Echo tracking
Surface echo tracking
Use these settings to configure how the transmitter should keep track of the surface.
These are advanced settings. Normally, they should not be changed.
Table C-8: Surface Echo Tracking
Parameter
Search window size
Track first echo
Related information
Handling ghost echoes in still pipes
Double surface handling
If there are multiple products in the tank, the Double Surface Handling function can be
manually set to allow user to select if the upper or lower product should be used as output.
The upper and lower surface echoes must be stronger than any disturbance echoes in the
search region for Double Surface Handling to function properly.
Table C-9: Double Surface Handling
Parameter
Track upper surface
Track lower surface
Upper product dielectric constant
Rosemount 5408 and 5408:SIS Level Transmitters
Configuration parameters
Description
This parameter defines a window centered at
the current surface position where new surface
echo candidates can be selected. The size of the
window is ±Search Window Size. Echoes outside
this window will not be considered as surface
echoes.
If there are rapid level changes in the tank, the
value of the Search Window Size can be
increased to prevent the transmitter from
missing level changes. On the other hand, a
large value may cause the transmitter to select
an invalid echo as the surface echo.
Select the Track First Echo check box if the first
echo above threshold always should be
considered as the surface echo.
Description
Track upper surface when there are multiple
products in the tank (for example thin oil layer
on top of water).
Track the lower product surface, such as the
interface when there are multiple products in
the tank, or the product surface instead of a
foam layer.
Enter the dielectric constant for the upper
product. A more precise value results in better
accuracy for the lower surface level.
February 2020
269