Simrad ER60 - REV B Operator's Manual page 42

Simrad ER60 Operator manual
Note
34
However, this is only possible if the split beam transducer has
been correctly installed.
Data editing
In both the Information and Plot views, you may perform data
editing in the sense of excluding or including an accepted single
echo detection. A left or right mouse click will act as a toggle
function for this editing. The model is completely recalculated
for each change.
In the Information view, a suspended single echo will be
identified with an asterisk (*) on the left side of the view.
The Plot view will draw an "empty" circle to indicate
suspension of the single echo entry.
The data deviation from the beam model should for a good
calibration give a RMS value less than 0.2 dB. If unwanted
echoes have been observed during data collection, these should
preferably be removed from the file. If, when collecting data,
fish swim into the layer that includes the reference target, then
note where in the file this happens, and delete these echoes
before the beam data are updated. Data with large deviation
from the calculated curve are may be caused by poor acoustic
conditions or by back scattering objects other than the reference
target. Isolated echoes with large deviation from the calculated
beam pattern can be removed, but when a large amount of the
collected data diverge from the average, this indicates that the
acoustic conditions has been unfavourable. When the RMS
value is in between 0.2 and 0.4dB, this indicates conditions is
not perfect but still acceptable. When the RMS value is higher
than 0.4 dB the calibration is poor, and should preferably be
rejected and not used for updating of the transducer parameters.
Updating transducer parameters
When you are satisfied with the calibration results you can use
the results to update your transducer parameters in the echo
sounder.
1 In the Calibration window, open the File menu and
choose Update Beam Data to perform this task.
This is a serious operation, which will affect the transducer
installation parameters and will thus affect all future results to
be obtained using the current transducer and pulse duration.
Thus, to prevent accidentally use of this operation, you are
asked to confirm this operation.
The changes take effect automatically the next time you start
normal operations on the echo sounder.
850-164692 / Rev.B