Emerson Rosemount 5408 Reference Manual page 209

Reference Manual
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Table B-6: Empty Tank Handling
Parameter
Empty tank detection area
Bottom echo visible when tank is empty
Related information
Enable bottom echo visible when tank is empty
Tank bottom projection
The Tank Bottom Projection is used to enhance measurement performance near the
bottom of the tank. When the tank bottom echo is strong (typical for flat tank bottoms)
and the dielectric constant of the product is low (e.g. oil), the transmitter may lock on
the bottom echo and report a false level measurement (empty tank). This problem can be
solved by using the Tank Bottom Projection function.
Table B-7: Tank Bottom Projection
Parameter
Bottom product dielectric constant
Maximum projection distance
Minimum tank bottom amplitude
Related information
Use tank bottom projection
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.
Rosemount 5408 and 5408:SIS Level Transmitters
Configuration parameters
Description
The Empty Tank Detection Area defines a range
where it is accepted to lose the echo from the
product. If the echo is lost in this range, the tank
is considered empty and the level is presented as
0.
When the tank is empty, the transmitter looks in
this range for the product surface. When a new
echo is found in this range, it is considered to
be the product surface. Therefore, if there are
disturbance echoes in this area, they may need to
be filtered out.
This function requires the Bottom echo visible
when tank is empty parameter to be disabled.
Only enable this parameter if the bottom echo
is visible when tank is empty. By setting this
parameter, the bottom echo will be treated as
a disturbance echo to facilitate tracking of weak
surface echoes close to the tank bottom.
Description
Enter the product dielectric constant for the
product in the bottom of the tank.
This defines the range where the function is
active. Enter the maximum distance from the
zero level (tank bottom).
Enter the minimum allowed amplitude for the
echo from the tank bottom before this function
is activated.
March 2023
209