RBRcoda T.ODO (ODO)

RBR standard instruments with an "ODO" in the name, such as the RBRconcerto3 C.T.D.ODO.quad (Fig. 27), use our RBRcoda T.ODO integrated sensors, deployable at depths up to 6000m.

RBRconcerto³ C.T.D.ODO.quad - Perspective - Horizontal.151.png
Fig. 27.    RBRconcerto³ C.T.D.ODO.quad with an ODO sensor (RBRcoda T.ODO)

Overview

The measurement principle of optical dissolved oxygen sensors is based on the luminescence quenching by oxygen.

During deployments, always orient the sensor downwards to reduce debris collecting at the aperture and minimise direct sunlight. Store the sensor in the dedicated storage cap, included with the instrument. Rehydrate for five days before deployment. See RBR ODO sensor care and maintenance for more information.

Specifications

Parameter Value

Measurement range

0-1000μmol/L

Calibrated range
Concentration
Saturation
Temperature

 
0-500μmol/L
0-120%
1.5 to 30°C

Initial accuracy
For | fast
For standard, | slow

 
Maximum of ±8μmol/L or ±5%
Maximum of ±2μmol/L or ±1.5%

Resolution
For | fast
For standard
For | slow

 
<1μmol/L (saturation 0.4%)
<0.5µmol/L (saturation 0.2%)
<0.1μmol/L (saturation 0.04%)

Time constant

<1s | fast, <8s standard, <30s | slow

Optical dissolved oxygen measurements require pressure correction for highest accuracy. When installed on an instrument with a pressure sensor, this correction is done automatically.
If installed on a moored instrument with no pressure sensor, enter the known absolute pressure value manually in the table under the Parameters tab in Ruskin.

Calibration equations

Uncompensated concentration

Corrected phase shift

\[\phi = c_2 + c_3\phi_{corrected}\]

Concentration in μMol/L

\[\begin{aligned} C(t,\phi) &=c_{4} + c_{5}t + c_{6}t^{2} + c_{7}t^{3} \\ &\quad + c_{8}\phi + c_{9}\phi t + c_{10}\phi t^{2} + c_{11}\phi t^{3} \\ &\quad + c_{12}\phi^{2} + c_{13}\phi^{2} t + c_{14}\phi^{2} t^{2} + c_{15}\phi^{2} t^{3} \\ &\quad + c_{16}\phi^{3} + c_{17}\phi^{3} t + c_{18}\phi^{3} t^{2} + c_{19}\phi^{3} t^{3} \\ &\quad + c_{20}\phi^{4} + c_{21}\phi^{4} t + c_{22}\phi^{4} t^{2} + c_{23}\phi^{4} t^{3}. \end{aligned}\]

Linear adjustment of the uncorrected concentration

\[C_u =c_0 + c_1C(t,\phi)\]

Derived parameters: oxygen saturation