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Configuration options & accessories
Reliable
detection of deep ocean tsunami waves without generating false alarms requires a
sensor that accurately detects pressure changes of millimeter scale while
sampling rapidly enough to characterize the shape of the tsunami waves and
reflections in real-time.
In addition to having extremely high resolution, the acquisition circuitry must be low power and free of noise, drift, and temperature-induced changes. The pressure sensor must be extremely reliable, stable, and capable of generating high resolution outputs.
Sea-Bird’s tsunami sensor continuously measures, records, and outputs pressure at user-programmable periods. Pressure resolution is better than 1 mm at full ocean depth (7000 meters), at the default sample period of 15 seconds. The tsunami sensor's sole purpose is to function as the heart of a deep ocean tsunami detection system. Setup and operation require no user interaction. A power supply supervisor and watchdog timer ensure automatic recovery if power or normal operation is interrupted.
The SBE 54 combines a Paroscientific Digiquartz® pressure transducer, microcontroller, real-time clock with temperature-compensated crystal oscillator, precision temperature-compensated reference frequency, two high-resolution frequency acquisition circuits, EEPROM, and FLASH memory. The reference frequency used to acquire pressure and pressure temperature outputs from the Digiquartz pressure sensor is accurate to 1 part per million and temperature calibrated to 50 parts per billion. The pressure sensor, reference frequency, and acquisition circuits are powered continuously to eliminate errors caused by start-up transients. Pressure and pressure temperature are acquired simultaneously to eliminate phasing errors and increase measurement resolution in each channel.
Low power consumption makes multi-year, battery-powered deployments practical. The FLASH memory provides four years continuous backup of the entire raw pressure record, at the default 15-second sample period. Preserving the entire time series in memory allows a post-deployment engineering review of the instrument’s performance, as well as a scientific analysis of the entire deployment record. The EEPROM stores calibration coefficients and diagnostic information. The Digiquartz pressure sensor and the frequency reference are tested and re-characterized at Sea-Bird to meet the demanding millimeter-scale sensitivity requirements.
CONFIGURATION AND OPTIONS
A standard SBE 54 Tsunameter includes:
Options include:
SOFTWARE
The SBE 54 is supplied with Windows 2000/XP software for instrument setup, data upload, and data conversion.
SPECIFICATIONS
| Data output | Real-time Pressure in ASCII engineering units (dbar, psia) every 1 - 240 seconds (default 15 seconds) |
| Measurement resolution ++ |
1.1 x 10 -7 of Digiquartz pressure range at
default 15-second sample period (0.0011 psia [0.8 mm] with 10,000 psia sensor) |
| Power supply | 12 – 28 VDC |
| Power consumption |
0.015 Watts at 15V, 0.016 Watts at 20V, 0.0018 Watts at 24V, 0.022 Watts
at 28V (running continuously) |
| Battery endurance |
12 Alkaline D cells: 14 months (80% capacity) 6 Lithium DD cells: 37 months (80% capacity) |
| FLASH memory | 8.9 million samples (51 months at default 15-second sample period) |
| Reference frequency |
Initial accuracy: 1 ppm Temperature characterization: ± 0.1 x 10 -6 (-10 to 30° C), ± 0.05 x 10 -6 (0 to 10° C) Aging: 3 x 10 -6 first year, 1 x 10 -6 after first year |
| Real-time clock | Quartz TCXO watch-crystal, accuracy ± 2 ppm (5 sec/month) |
| ++ The sum of all uncertainties in a measurement of pressure change is less than 1 mm over a duration of a few minutes and less than 5 mm over a duration of minutes to hours, including ocean/instrument temperature changes of 0.25° C. | |
SBE 54 with optional long housing with
battery compartment
ADDITIONAL INFORMATION / LINKS:
Documentation -- manual, photos, technical papers, application notes, etc.
Sales Information -- options, accessories, cables, mount kits, spares, etc.
Software -- components of Seasoft V2
Links to Other Instruments of Interest
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Specifications are subject to change without notice.