7.10.3
Double bounce handling
A double bounce echo occurs when a radar signal bounces back and forth between the
product surface and the tank roof before it is detected by the transmitter. Double bounces
are most likely to appear in metal water tanks. When using interface measurement to
detect a potential oil layer on top of the water, an unidentified double bounce echo peak
could cause problems being interpreted as an interface echo peak.
Normally, these echo peaks are identified and discarded as double bounce peaks by the
Rosemount 5300. Both the echo peak amplitude and position are used to identify a double
bounce.
Figure 7-33: Double Bounce Echo Peak Position
$
'
%
&
*
(
)
)
+
A. Surface distance
B. Nozzle height
C. Distance to potential double bounce = Surface distance
×
2
D. Distance to potential double bounce = (Surface distance
×
2) - Nozzle height
E. Surface echo peak
F. Double bounce echo peaks
G. Signal amplitude
H. Distance
Required settings for effective double bounce identification
•
The position of a potential double bouce echo peak is related to the nozzle hight. A
properly configured nozzle height is therefor essential to achieve an efficient double
bounce handling.
Service and troubleshooting
Reference Manual
April 2019
00809-0100-4530
232
Rosemount 5300 Level Transmitter