Premium CTD Temperature Sensor
SBE 3plus

Print version     Configuration options & accessories

DESCRIPTION

The superior performance of the SBE 3plus results from its optimized electronic design, superior calibration, response characterization, and quality testing program. The SBE 3plus is a more rigorously tested and calibrated version of our SBE 3F temperature sensor. A sensor is designated as an SBE 3plus only after demonstrating drift of less than 0.001 °C during a six-month screening period. In addition, the time response is carefully measured and verified to be 0.065 ± 0.010 seconds.

Every SBE 3plus is calibrated in Sea-Bird's computer-controlled calibration baths. These super-low-gradient baths produce temperature calibrations with resolution and accuracy not previously available to oceanographers.

These sensors can be successfully calibrated as separate modules, because they have built-in acquisition circuits and frequency outputs. When used with a Sea-Bird CTD, the overall system accuracy is limited only by the accuracy of the CTD's master clock. Errors from this source are demonstrably negligible (in the SBE 911plus CTD, clock error contribution is 0.00016 °C based on a five-year worst case error budget, including ambient temperature influence of 1 ppm total over -20 to +70°C, 1 ppm first year drift, and four additional year's drift at 0.3 ppm per year).

APPLICATION

Intended primarily for use on the SBE 911plus CTD system, the SBE 3plus can also be used as a component in custom oceanographic systems or for high-accuracy industrial and environmental temperature-monitoring applications. Depth ratings to 6800 and 10500 meters (22,300 and 34,400 ft) are offered to suit different application requirements.

OPERATION

The sensing element is a glass-coated thermistor bead, pressure-protected inside an 0.8 mm (0.03 in.) diameter thin-walled stainless steel tube. Exponentially related to temperature, the thermistor resistance is the controlling element in an optimized Wien Bridge oscillator circuit. The resulting sensor frequency is inversely proportional to the square root of the thermistor resistance and ranges from approximately 2 to 6 kHz, corresponding to temperatures from -5 to +35 °C.

SPECIFICATIONS

Range: -5.0 to +35 °C

Resolution: 0.0003 °C at 24 samples per second (with SBE 911plus CTD)

Initial Accuracy: ± 0.001 °C (NIST-traceable calibration applying over the entire oceanographic range)

Stability: Must demonstrate less than 0.001 °C drift during the 6 months prior to delivery

Response Time: 0.065 ± 0.010 seconds (time to reach 63% of final value following a step change in temperature; water velocity 1 m/s)

Self-heating Error: < 0.0001 °C in still water

Settling Time: < 0.5 seconds to within 0.001 °C

Power required: 11 - 16 VDC, 25 ma

Signal Output: ± 0.5V square wave

ADDITIONAL INFORMATION / LINKS:

Documentation -- manual, photos, technical papers, application notes, etc.

• Print version of this specification sheet / brochure
• General SBE 3 Calibration Data
• Application Notes:
  - 42: ITS-90 Temperature Scale
  - 71: Desiccant Use and Regeneration (drying)

Sales Information -- options, accessories, cables, mount kits, spares, etc.

• Configuration options & accessories:
  - Details for SBE 3plus
  - Listing for all products
• Cables
• Mount kits
• Spare parts

Links to Other Instruments of Interest

• Other temperature sensors:
  - SBE 3F -- same response time as 3plus, but less rigorously tested
  - SBE 3S -- slow response version of SBE 3
  - SBE 35 -- laboratory standards thermometer for use in fixed point cells and depths up to 6800 m
  - SBE 35RT -- digital reversing thermometer, can be used with SBE 32 Carousel Water Sampler to measure temperature each time a bottle is fired
  - SBE 38 -- digital oceanographic thermometer with RS-232 or RS-485 output, standards-level performance
  - SBE 39plus -- high-accuracy temperature recorder with RS-232 output and internal USB interface, internal battery and non-volatile memory, plus optional pressure (NEW, February 2014)
  - SBE 39 -- high-accuracy temperature recorder with RS-232 output, internal battery and non-volatile memory, plus optional pressure
  - SBE 39-IM -- high-accuracy temperature recorder with inductive modem telemetry, internal battery and non-volatile memory, plus optional pressure
  - SBE 56 -- high-accuracy temperature recorder with internal battery, non-volatile memory, and USB upload
• SBE 9plus CTD -- uses SBE 3plus as standard equipment

Specifications are subject to change without notice.

Sea-Bird Home     Phone: (+1) 425-643-9866     E-mail: seabird@seabird.com