RBRcoda ODO

The RBRcoda ODO (Fig. 5) uses the optical dissolved oxygen sensor, with three time constant options available: 1s, 8s, and 30s. The | fast (1s time constant) variant is well suited for profiling applications. The | slow (30s time constant) version has a protective layer to facilitate automated cleaning by a wiper to keep it free from biofouling during long-term moored deployments.

During deployments, always orient the sensor downwards to reduce debris collecting at the aperture and minimise exposure to 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.

RBRcoda3.T.ODO.angled.fast and slow.png
Fig. 5.    RBRcoda ODO | fast and RBRcoda ODO | slow

Dissolved oxygen

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 deployed as a standalone sensor or 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.

Temperature

Parameter Value

Range1

-5°C to 35°C

Initial accuracy

±0.002°C

Resolution

<0.00005°C

Typical stability

±0.002°C / year

Time constant

<1s

1A wider temperature range is available upon request. Contact RBR for more information.

Physical

Parameter Value

Connector

MCBH-6-MP

Communications

RS-232

Housing

Titanium

Diameter

28mm

Length

~125mm, (~160mm with connector)

Weight

180g in air, 110g in water

Depth rating

Up to 6000m

Sampling rate

24hr to 1Hz

Power

Parameter Value

Supply voltage

7V to 15V (12V nominal)

Power

10mA for 300ms (36mJ/sample) | fast
10mA for 300ms (36mJ/sample) standard
10mA for 500ms (60mJ/sample) | slow

Sleep current

60μA

Output values

  • Temperature (°C)

  • Dissolved O2 concentration (μmol/L)

  • Dissolved O2 concentration (salinity compensated, μmol/L)

  • Dissolved O2 saturation (%)

  • Dissolved O2 phase (°)

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

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