deri_depth - derivation of depth from absolute pressure

This derived channel implements a simplified equation for water depth in meters, in which no account is taken of either geographical variations in the Earth's gravitational field, or the variation of water density with depth: both these quantities are treated as constants.

In the form used by the logger, using an RBRconcerto³ C.T.D as an example, this becomes:

where

n0 is the label of the pressure channel, pressure_00 in the example.
n1 is the label of the atmospheric pressure channel; not present in the example (default value, refer to parameters atmosphere).
p is the value set for the density of water using the "parameters density" command, g is a fixed constant 0.980665, representing the standard value of acceleration due to gravity, in units which correctly account for pressures being measured in decibars.
Dm is the calculated depth in meters.

Examples

CODE

>> calibration depth_00 equation
<< channel depth_00 equation=deri_depth

Confirm the equation type.

CODE

>> calibration depth_00
<< calibration depth_00 datetime=20251001000000 equation=deri_depth offset=0.0000000e+000 slope=1.0000000e+000 n0=pressure_00 n1=value

Request confirmation of all calibration coefficients.