Rosemount 5600 Series, Справочное руководство

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Reference Manual
00809-0100-4024, Rev BA
September 2005
Rosemount 5600 Series
4-16
Surface Tracking
Slow Search This variable controls how to search for the surface if a surface
echo is lost. With this parameter set the transmitter starts
searching for the surface at the last known position, and
gradually increases the width of the search region until the
surface is found. If this variable is not set the transmitter
searches through the whole tank. This parameter may typically
be used for tanks with turbulent conditions.
Slow Search Speed If the surface echo is lost, the transmitter starts to search
around the last known level to find the surface echo again. This
parameter indicates how fast it should expand the search
window.
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 partly transparent to the radar signal.
If this function is activated, you can specify which surface to
select by using the Select Lower Surface parameter.
Upper Product DC This is the dielectric constant for the upper product. A more
precise value results in better accuracy for the lower surface
level.
Level above min distance
possible If the surface echo is lost in the vicinity of the antenna, full tank
is indicated and searching for the surface echo is limited to a
region close to the antenna.
Select Lower Surface This function should only be used if Double Surface is set. If
Select Lower Surface is set the lower surface will be presented
as the product surface. If not set the upper surface is tracked.
Echo Timeout Use Echo Timeout to define the time in seconds before the
transmitter will start to search for a surface echo after it has
been lost. After an echo has been lost, the transmitter will not
start searching or set Invalid Level until this time has elapsed.
Close Distance Window This parameter defines a window centered at the current
surface position in which new surface echo candidates can be
selected. The size of the window is ±CloseDist. Echoes outside
this window will not be considered as surface echoes. The
transmitter will immediately jump to the strongest echo inside
this window.
If there are rapid level changes in the tank, the value of the
Close Distance Window could be increased to prevent the
transmitter from missing level changes. On the other hand, a
value too large might cause the transmitter to select an invalid
echo as the surface echo.