Emerson Rosemount 5408, Справочное руководство

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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 Description
Search window size 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.
Track first echo Select the Track First Echo check box if the first
echo above threshold always should be
considered as the surface 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 Description
Track upper surface Track upper surface when there are multiple
products in the tank (for example thin oil layer
on top of water).
Track lower surface 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.
Upper product dielectric constant Enter the dielectric constant for the upper
product. A more precise value results in better
accuracy for the lower surface level.
Reference Manual Configuration parameters
00809-0100-4408 February 2020
Rosemount 5408 and 5408:SIS Level Transmitters 269