Operating Manual

Chapter 5 Radar Fine Tuning Accu-Wave
5-12 TN Technologies
The second line shows that the Q1 echo quality factor for echo 2 is 180 (larger values
indicate better quality). The distance of echo 2 relative to the reference line on the sensor is
33.75 ft.
The third line shows that the Q2 echo quality factor for echo 2 is 45 (again larger values
indicate better quality). The signal strength of echo 2 is 22.11, before any weighting
factors or other selection modifiers are applied.
Finally, the fourth line of the display shows the value of the Successive Weighting Factor
(SWF).
Limiting the Number of Echoes to Process
The system only analyzes echoes that fall in the range of interest (ROI) and that are
stronger than the minimum signal strength. The ROI is initially defined by the primary
measurement setup entries. To limit the number of echoes processed, you can modify the
range of interest. You can also modify the values for the “maximum number of echoes to
be processed” (default value is 8) and/or the “minimum allowable signal strength” (default
value is 3). Using the default values, the strongest echoes (up to 8) with signal strength > 3
are considered as the candidate echoes. The “Clutter Data Management” menu items can
be used to remove “phantom” echoes which fall within the ROI. To optimize Accu-Wave
performance, you should constrain the set of candidate echoes to the smallest group that
will reliably include the desired echo (echo from process material).
Note: Only a few of the Radar Fine Tuning tools actually alter the echo report -
the minimum allowable signal strength, the maximum echo count to
process, the clutter data management, and modifying the range of interest
(ROI).
None of the other Radar Fine Tuning tools alter the echo report. These
other tools and weighting factors are applied to the signal strength in the
echo report to select the best echo from the set of echo candidates.
Echo Rejection
Several of the menu items under the “False Echo Management” menu are used to reject
unwanted echoes. These items do not alter the echo report, but do modify the echo
selection process. The three tools used to eliminate echoes from being considered as
candidate echoes are:
1. The “maximum desired signal strength” can be used to reject echoes that are
stronger than the desired echo. This capability may be used to reject very strong
false echoes while allowing the weighting factor to be set to deal with other
situations.
2. “Q1 and Q2 quality factor rejection” criteria can be used to reject any echo which
has a low Q1 and/or Q2 quality factor value.
3. “Tank mapping” can be used to specify the location of physical targets within an
empty tank and have the gauge ignore echoes from these targets. (See “Tank Map
Setup” on page 5-21.)