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, although the water density can be changed using the "settings density" command. In the form used by the logger, using an RBRconcerto³ C.T.D as an example, this becomes:
where

• n0 is the index of the pressure channel, 3 in this case,
• n1 is the index of the atmospheric pressure channel; not present in this example, so set to "value".
• p is the value set for the density of water using the "settings 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.