TideMaster - Operating Manual: MANUAL-1094978189-1 | issue: 1.1
© 2021
– Valeport Ltd
Page | 28
7.1.2 User Calibration
If USER calibration method is set, the unit will set itself to output data calibrated according to user input Gain
Factor and Datum Offset.
The relationship between depth and pressure for shallow water can also be expressed as:
Depth =
Pressure
Density × Acceleration due to Gravity
+ Offset
Where:
Pressure is measured in Pascals (1Bar = 105 Pascal, therefore 1 dBar = 104 Pascal)
and, (Density * Acceleration due to Gravity)-1 is the Gain Factor
7.1.2.1 Gain Factor
Fresh Water
Using a standard density of 994 kg/m3 [pure water at 15°C] and a gravity figure of 9.81m/s2
Depth
(
m
)
=
104
994
×
9.81
then 1 decibar = 1.025 metres water depth
Therefore, Gain Factor = 1.025
Sea Water
Using a standard density of 1025.97 kg/m3 [standard seawater at 15°C] and a gravity figure of 9.81m/s2,
Depth
(
m
)
=
104
1025.97
×
9.81
then 1 decibar = 0.993 metres water depth
Therefore, Gain Factor = 0.993
If the user knows the density of the water (by using a hydrometer) and the local gravity value, the Gain
Factor can be calculated.
