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Reference Manual
00809-0100-4026, Rev HA
Appendix C: Advanced configuration
November 2014
Advanced Configuration
C.3.5 Surface echo tracking
Slow search
This variable controls how to search for the surface when a surface echo is lost. With this
parameter set, the transmitter starts searching for the surface at the last known level and
gradually increases the search region until the surface is found. If this variable is not set, the
transmitter searches the whole tank. This parameter is typically used for tanks with turbulent
conditions.
Slow search speed
This parameter indicates the speed the search region (Slow Search window) is expanded when
the Slow Search function is active.
Double surface
Indicates that there are two liquids or foam in the tank resulting in two reflecting surfaces. The
upper liquid or foam layer must be partially transparent to the radar signal.
The Select Lower Surface parameter specifies the surface layer selected as the surface.
Upper product dielectric constant
This is the dielectric constant for the upper product if there is a double surface situation. A more
precise value results in better accuracy for the lower surface level.
Select lower surface
This function should only be used if Double Surface is set. If Select Lower Surface is set, the lower
surface is identified as the product surface. If not, the upper surface is used.
Echo timeout
Echo Timeout defines the time, in seconds, after the echo has been lost, before the transmitter
starts searching for a surface echo. The transmitter will not start searching, or trigger any
alarms, until this time has elapsed.
Close distance window
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 ±CloseDist. Echoes outside this
window will not be considered surface echoes and the transmitter will jump to the strongest
echo inside this window. If there are rapid level changes in the tank, the value of the Close
Distance Window 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.
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