Stop Recorder Deployment
·
Select Stop Recorder Deployment. When data acquisition has stopped a dialog
will display the current instrument and PC clock time.
Data Retrieval
·
Select Recorder Data Retrieval.
·
The recorder overview dialog will show a list of all files currently stored in the
recorder, including the time of the first measurement and the size for each file.
·
Select a file in the list by clicking on the filename. Press Retrieve to specify the
name and disk location of the file.
Tip! Check the retrieved data before deploying the instrument for the second time. If
something is wrong with the instrument, the configuration or the deployment, this will
be detected and the possibility of making the same mistake twice is avoided.
Data Conversion
·
To convert binary data files retrieved from the recorder to a readable ASCII format,
select Data Conversion.
·
Add files to the Files to convert list by using the Add file... file selection dialog.
Select the file to convert in the list and press the blue arrow. Specify the location for
the converted files in the Save in folder field. An optional prefix or suffix that will be
added to the recorder filename may be specified. Select from the View files drop-
down list to open the converted (ASCII) files in e.g. Notepad.
On-line Data Collection
·
Select Start Data Collection from the On-line menu (or press the toolbar button) to
start data acquisition. The real time display shows velocity data and sensor data as
it is collected.
·
To capture the data that comes in over the serial port to disk select Disk
Recording… from the On-line menu and define the name of a file (without
extension). Once this disk file is defined, the Start Disk Recording and Stop Disk
Recording menu items and toolbar buttons will be enabled.
·
The output can either be in ASCII, in fixed NMEA format, or binary format. Note: To
output NMEA, use the Activate Serial Output option in the Deployment planning
(needs a ProLog installed).
ProLog
The Nortek Processor and Logger (ProLog) is a micro-computer with a 4GB recorder
located on a separate circuit board inside the AWAC. Its primary function is to reduce
raw wave data to standard wave estimates for online applications. Reduction of wave
data is valuable when considering low bandwidth communications (e.g. acoustic
modems, satellite). To learn more about the ProLog option visit the website.
Mounting
Proper mounting of the instrument is crucial for successful collection of data. Please
mount the instrument in accordance with the Mounting Guidelines in the
Comprehensive Manual.
Basic principles
The AWAC measures current
speed and direction by
transmitting sound w aves that
are reflected by particles drifting
w ith the currents in the w ater.
The Doppler shift of the return
signal is proportional to the
velocity component along the
beams. By combining the
Doppler shifts from the three
beams, the 3D velocity is
calculated.
AST – Acoustic Surface
Tracking
The vertically oriented
transducer in the center of the
AWAC is used to measure the
distance to the sea surface
directly by using the simple echo
sounder principle. The center
beam is used to transmit a very
short pulse (relative to the
Doppler measurements). The
travel time from the AWAC to the
surface and back allows us to
estimate the distance to the
surface for each ping.
Data analysis
The softw are supplied has been
designed to provide you w ith the
ability to set the instrument up
for deployment, upgrade the
firmw are, dow nload acquired
data and do a quality assurance
of them. The data can be
converted to ASCII format that
may be imported into various
post processing programs. In
addition, Nortek has developed a
series of real time and post
processing softw are packages
that simplify your analysis w ork.
These can be dow nloaded from
our w ebsite; contact Nortek for
a valid license key.
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