Emerson Rosemount 5900S Series Reference Manual page 96

Rosemount 5900S Series
Figure 4-6. The Extra Echo
Function
4-12
Activate Extra Echo Function
The Extra Echo Detection function is used for tanks with a dome or conical
bottom shape provided the tank bottom does not produce a strong echo when
the tank is empty. This function results in more robust measurements near the
tank bottom.
For tanks with a conical bottom, an echo may appear beneath the actual tank
bottom when the tank is empty. If the device is not able to detect the tank
bottom this function can be used to ensure that the device stays in empty tank
state as long as this extra echo is present.
You can find out if such an echo exists by using the Tank Scan function when
the tank is empty. Ensure that the scan extends below the tank bottom. The
tank spectrum can be used to find suitable values for parameters such as the
Extra Echo Min Distance, Extra Echo Max Distance and Extra Echo Min
Amplitude. The tank is considered empty when an echo appears within the
Min and Max Distance at an amplitude above the specified threshold.
Extra Echo Min Distance
Defines the minimum distance to the extra echo. This parameter should be
greater than the Tank Height.
Extra Echo Max Distance
Defines the maximum distance to the extra echo. This parameter should
be greater than the Extra Echo Min Distance.
Extra Echo Min Amplitude
Defines the minimum signal strength of the extra echo. If the signal
strength exceeds this value and is found in the region between Min
Distance and Max Distance, the device stays in empty tank state and
presents Level=0.
Reference Manual
00809-0100-5900, Rev CA
Amplitude
Section 4. Configuration
June 2014