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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
| Housing | Depth Rating | Weight |
| 7075 aluminum | 6800 m | 0.63 kg (1.4 lbs) in air; 0.28 kg (0.6 lbs) in water |
| 6Al-4V titanium | 10500 m | 0.90 kg (2.0 lbs) in air; 0.55 kg (1.2 lbs) in water |
ADDITIONAL INFORMATION / LINKS:
Documentation -- manual, photos, technical papers, application notes, etc.
Sales Information -- options, accessories, cables, mount kits, spares, etc.
Links to Other Instruments of Interest
Specifications are subject to change without notice.
Sea-Bird Home Phone: (+1) 425-643-9866 Fax: (+1) 425-643-9954 E-mail: seabird@seabird.com