July 2019 – TD 304 OPERATING MANUAL – Doppler Current Profiler Sensor
Page 71
3.5.3
Fixed Settings
Figure 3-18: Fixed Settings
Fixed Settings
are settings used in internal calculation.
Sound Speed (m/s
) is the fixed sound speed setting in m/s. This value is used for cell positioning in the profile and for
calculation of current speed values. Variable sound speed values can be used while sensor is running. Default value for
sea water is 1500.
Air Pressure (kPa
) is the barometric pressure in kPa used to compensate for air pressure. The default value is 101.3
Local Gravity Constant (m/s
2
)
is the local gravity constant in m/s
2
. The default value is 9.81m/s
2
Salinity (PSU
) is the Salinity in PSU used for calculation of density, sound speed and depth. The value can be altered
while sensor is running to compensate for variable salinity.
Fixed Installation Pressure (kPa)
is the pressure in kPa at the deployment site. The value can be altered while sensor
is running to compensate for variable pressure. NOTE! This value is used for calculation of and used to position cells
referenced to surface if surface cell or surface referenced cell are selected
Temperature (Deg.C
) is the temperature in degree centigrade. The value is used for calculation of Salinity, Sound
speed and Density. The value can be altered while sensor is running to compensate for variable temperature.
3.5.4
Calculations
Figure 3-19: Calculations
Under
Calculations
you find only one Property,
Enable Derived Sound Speed
. If enabled it will calculate the sound
speed from the other available sensors or fixed values. This overrides the Sound Speed setting. If a parameter is
available from another sensor it will use this in the calculation, otherwise it will use the fixed value.