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Aanderaa Data Instruments AS – TD302
CHAPTER 4
Installation and deployment considerations
Please refer Table 4-1 for the most important installation and deployment considerations.
Table 4-1 Installation considerations for the Pressure, Tide and Wave and Tide sensors.
Description
Measurement Parameters:
Pressure/
Temperature
Tide
Wave
Install the sensor with the top up
x
x
x
Install the sensor in a fixed installation
x
x
The deployment depth must be at least 1 meter below the
water surface (at the lowest tide level)
x
We recommend that the deployment depth is less than 15 m
x
Install the sensor with top up because the pressure inlet is filled with silicone oil. The sensor is calibrated for
top-up installations; other positions will produce a small zero offset.
Valid measurements of tide and wave parameters require a fixed installation on a vertically stable structure to
avoid movements of the sensor due to water conditions or settling.
For wave measurements the sensor should at all times be deployed at least 1 meter below the water surface to
ensure valid measurements. Low water levels require more internal calculations. If the water level becomes less
than 0.25 meters, the water level will be set to 0.25 meters.
The data quality of the wave measurements is reduced with increasing installation depth due to wave
attenuation, refer Appendix 4. The pressure variations generated by waves are damped, and the cut off
frequency reduces the frequency range in the wave spectrum. At depths larger than 20 meters the dampening is
difficult to compensate for because of a weak signal. The frequency range is also very limited.
If the Wave and Tide sensor or the Tide sensor is attached to a floating device the sensor cannot measure tide,
but can compute draft of the structure.
If the Wave and Tide sensor is attached to a very large floating device so that the sensor will be relatively steady
in relation to the mean sea level, then the sensor can measure waves with reduced quality. Such a large floating
device can be e.g. a floating fish farming facility or oil rig. We recommend installation on the sea floor or
attached to a fixed pillar. Installation on a string is not recommended because there will always be some
movement of the string/sensor.
IMPORTANT! Do not deploy the sensor deeper than the pressure rating of the pressure element.
