Nortek DVL 1000 300m, Руководство пользователя

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DVL 14
© 2017 Nortek AS
5 Preparation
From this point on it is assumed that a stable, reliable connection with the instrument has been
established. This is necessary to continue onwards for the next few sections of the manual. If the
instrument is unable to connect with your PC please revisit the
Getting Started chapter or consult
the Troubleshooting chapter.
5.1 Functionality Test
Before every mission, it is strongly recommended that a functionality test is performed to ensure that
the various components work as intended. Before continuing make sure that your instrument is
connected as described in
Initial Ethernet Connection . The Functionality Test for the pressure and
temperature sensors may be performed by observing the data output in the Display Data (as plots or
text) page of the web browser interface.
Temperature
To test the temperature sensor simply read off the corresponding value and compare with your room
temperature.
Pressure
The pressure sensor outputs the absolute pressure value in units of dBar. During production, the
sensor is adjusted to 9.5 dBar to output the gauge pressure (pressure relative to the atmospheric
pressure). The pressure sensor cannot output negative values. In air, the pressure sensor will output
a value of 0.2-0.7 dBar, depending on atmospheric conditions. Test the pressure sensor by
submerging the instrument in approximately 0.5 m of water. The value should read 0.5dBar + the
ambient pressure of 0.2-0.7. An alternative way to test whether the sensor is functioning is by
forming a seal around the sensor with your mouth and blowing to observe an increase in pressure.
Recorder
Note: We recommend starting new missions with an empty recorder if you plan to store data
internally. Before you erase the recorder, make sure that you have transferred all the data you want
to retain.
Go to the Web interface > Maintenance > Erase SD card.
Or use the ERASE,9999 command (ref. DVL integrator's Guide)
Transducers
A functionality test of the bottom track is often difficult in a laboratory setting. This is because the
acoustic conditions of buckets or tanks are not representative of in-field conditions and more often
than not it just does not work. What is most important to evaluate is the response of the
transducers and not the bottom track capabilities in bucket. The following outlines how one can
confidently evaluate each of the four transducers
In order to confirm that the transducers are functional, one will need to evaluate the change in
response as the DVL pings in the air verses how it pings in the water. This may be done by enabling
the current profile mode in the measurement configuration and to include only a single cell (no
current profiling license required). The configuration is illustrated in the screen shot below. Once the
configuration is complete and the DVL is pinging, you may submerge the DVL in water (a bucket will
do). You will see that the amplitude in this first cell will increase from its noise floor (approximately
27 dB) to a large amplitude (approximately 85 dB). Screen shots for measurements in-air and in-
water are shown below.