Double Bounce - Emerson Rosemount 5402 Reference Manual

Reference Manual
00809-0100-4026, Rev KC
C.5.3

Double bounce

A double bounce echo is an echo that has been reflected against the tank roof then down to the surface
before being detected by the transmitter.
Double bounces are commonly present in spherical or horizontal cylinder tanks. In this case, the tank
roof can sometimes amplify the double bounce echo amplitude. Normally, double bounce echoes
appear when the tank is 60-70% full. In these cases, the double bounce echo can cause the transmitter to
lock onto the wrong echo.
The Double Bounce function is used for managing problems with echoes appearing in the tank because
of the tank shape stronger than the surface echo itself.
The Double Bounce Offset is given by the following formula:
Double Bounce Offset = B - 2*A,
where A is the distance from the Tank Reference Point to the product surface, and B is the distance from
the Tank Reference Point to the Double Bounce echo. In many cases, the Double Bounce Offset is given
by the height of the nozzle.
Note that the surface echo is required to suppress the double bounce. If the surface echo enters the hold
off distance region, there is no product surface reference and the double bounce might be interpreted as
the surface echo.
A
Advanced Configuration
B
Double bounce offset=B - 2*A
Amplitude
Advanced Configuration
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