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RBRduet⁴ dual sensor logger

Our most compact, lightweight, and versatile dual channel logger.

Infinite memory*
Any AA battery chemistry
Standard sampling up to 2Hz, and optionally up to 32Hz
USB-C download
Optional fast sampling, tide, and wave

*not really, but we stopped counting at billions.

T.Dtemperature, pressure
D.Tu |2xpressure, turbidity
D.chl-a |2xpressure, chlorophyll-a
D.ODO |2xpressure, temperature, optical dissolved oxygen

Downloads

RBR Quick Start Guide: Compact Instruments⁴ RBR Instrument Guide: Compact Instruments⁴ Ruskin User Guide: Compact Instruments⁴

Features & Configurations

long deployments

compact and lightweight

Two aa batteries

UP TO 32Hz SAMPLING

USB-C download

Infinite memory^*

*not really, but we stopped counting at billions

RBRduet⁴ loggers are compact, lightweight instruments designed for high-precision oceanographic measurements in demanding environments. They combine exceptional accuracy and resolution using any standard AA battery chemistry.

Engineered for durability in harsh marine conditions, the RBRduet⁴ delivers reliable, long-term performance across a wide range of oceanographic applications.

Optional Configurations

\| fast32	up to 32Hz continuous sampling
\| tide32	continuous sampling or tidal averaging
\| wave32	continuous sampling, tidal averaging, or wave burst
\| deep	depths up to 10000m
\| 2x	double the power of RBRduet⁴ T.D

Specifications

Physical
Power	Any AA cell(s)
Communication	USB-C
Storage	Infinite memory*
Clock drift	±60 seconds/year
Depth rating	up to 1700m (plastic), up to 10000 (Ti)
Diameter	~25mm
Length	Varies per sensor
Weight (air)	Varies per sensor
Weight (water)	Varies per sensor

*Not really, but we stopped counting at billions.

Temperature
Calibrated range^Footnote*	-5°C to 35°C
Initial accuracy	±0.002°C
Resolution	<0.00005°C
Typical stability	±0.002°C/year
Time constant	<1s standard, <0.1s \|fast

^*A wider temperature range is available on request. Contact RBR for more information.

Pressure
Calibrated range^Footnote 1	20 / 50 / 100 / 200 / 500 / 1000dbar (plastic)
	2000 / 6000 / 10000dbar (Ti)
Initial accuracy^Footnote 2	±0.05% full scale
Resolution	<0.001% full scale
Typical Stability	±0.05% full scale / year
Time constant	<10ms

¹Recommended depth for wave measurements is less than 50m.

²±0.01% full scale is available upon request. Contact RBR for more information.

Turbidity
Wavelength	880nm
Centroid angle	90°
Linearity, R	0.99
Initial accuracy	5%
Calibrated range	0 – 1000FTU
Measurement range^Footnote *	0 – 1500FTU

^*Response becomes non-linear above 1000FTU.

Turbidity (optical backscatter)
Wavelength	880nm
Centroid angle	135°
Linearity, R²	0.99
Initial accuracy	5%
Calibrated range	1000-4000FTU
Measurement range^Footnote*	0 – 20000FTU
Detection limit	2.0FTU

^* Response becomes non-linear below 500FTU and above 15000FTU.

Chlorophyll-a
Wavelength	470nm/695nm (excitation/emission)
Calibrated range^Footnote*	0-50µg/L
Measurement range	0-500µg/L
Detection limit	0.02µg/L

^* Scaled for the in vivo fluorescence response.

Optical
Linearity, R	0.99
Initial accuracy	5%

Oxygen
Calibrated range	0-500μM concentration 0 – 120% saturation 1.5°C to 30°C temperature
Initial accuracy	Maximum of ±8μmol/L or ±5% \| fast Maximum of ±2μmol/L or ±1.5% standard Maximum of ±2μmol/L or ±1.5% \| slow
Resolution	<1µmol/L (saturation 0.4%) \| fast <0.5μmol/L (saturation 0.2%) standard <0.1μmol/L (saturation 0.04%) \| slow
Time constant	<1s \| fast, <8s standard, <30s \| slow
Sampling rates	24hr to 1Hz

Output values

Temperature (°C)
Dissolved O2 concentration (μmol/L)
Dissolved O2 concentration (salinity compensated, μmol/L)
Dissolved O2 saturation (%)
Dissolved O2 phase (°)

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