In September 2018, RBR Ltd. introduced a new equation for the combined CT cell. Instruments manufactured after the 1st September 2018 are using this equation. The difference between the two corrections is a move from a first- to third-order polynomial for pressure dependence. |
Continuing with the RBRconcerto³ C.T.D.pH logger, the conductivity reading from Channel-1 without corrections is given by a simple linear function: where R is the normalized voltage ratio from Channel-1 monitoring conductivity, c0,c1 are the core coefficients of the linear equation, and Craw is the uncorrected conductivity output, reported in mS/cm for RBR marine instruments.
The equation which corrects the output for the effects of both temperature and pressure on the conductivity cell is: Casting the equation into the style used by the logger would give:
where
It is quite common to have a logger monitoring conductivity and temperature without a pressure channel, typically deployed at a known, constant depth. In this case, n1 would be set to "value", and so value(n1) would be substituted by a default value (see the "settings pressure" command).
Confirm the channel type.
Set the core coefficients.
Set the cross-channel correction coefficients.
Request confirmation of all calibration coefficients. |