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The SBE 53 BPR measures full ocean depth water level with extremely high resolution, accuracy, and stability. The BPR combines a uniquely precise and stable time base with low-power frequency-acquisition circuitry, Paroscientific Digiquartz® pressure transducer, non-volatile 32 MB FLASH memory, and a precision thermometer, to provide unprecedented bottom-pressure recording capability. An optional SBE 4M conductivity sensor can be added to provide salinity data.
The BPR integrates pressure measurements to obtain water levels (tides) unaffected by wave action. The interval between each water level measurement and the duration of the integration period are user-programmable. The interval is programmable over a range of 1 minute to 1 hour. The integration duration is programmable from 1 minute to the entire tide interval. The BPR can continuously power the pressure transducer and reference frequency oscillator, eliminating turn-on transients and providing the highest quality data. Alternatively, the BPR can be programmed to enter a power-down state between measurements to conserve battery power for very long deployments, with a user-specified warm-up period before each pressure measurement. Temperature data is recorded with each pressure integration. Logging (recording) can be programmed to start and stop at specified times after the instrument is deployed.
The pressure and internal temperature compensation signals (frequencies) from the transducer are integrated in parallel for the water level integration duration. The measurement times are set by a continuously powered, real-time clock with an accuracy of ± 5 seconds/month. Long-term drift of the counter's reference frequency is on the order of 1 ppm/year. To allow for correction of drift, an ovenized crystal oscillator is programmed to periodically make a reference frequency measurement.
Large memory and low power requirements permit frequent water level recording. For example, with standard alkaline batteries, a 420-day deployment could include water level measurements every 30 minutes (integrating pressure for the entire 30 minutes); a 2-year deployment could be achieved if pressure integration is limited to 4 minutes for each water level measurement, with a 15-minute warm-up of the pressure sensor and reference frequency oscillator before each measurement. Alternatively, deployments approximately 3 times longer are possible with Electrochem DD lithium batteries. Fast binary upload of data in memory can be accomplished at up to 115,200 baud.
Firmware upgrades can be downloaded via the serial interface without opening the electronics compartment.
CONFIGURATION AND OPTIONS
A standard BPR is supplied with:
The BPR includes Seasoft© for Waves, a comprehensive package of Windows programs for instrument setup and data retrieval, data conversion, and plotting.
|Pressure||Standard Temperature (°C)||High Accuracy Temperature (°C) optional||Conductivity (S/m) optional|
0 to 1300, 2000, 4000, or
(2000, 3000, 6000, or 10000 psia)
|-5 to +35||-5 to +35||0 to 7|
|Accuracy||0.01% of full scale ¹||0.01||0.002||0.001|
|Resolution||0.045 ppm (0.3 mm for 10,000 psia range, 1-minute integration, continuously powered)||0.001||0.0001||0.00002|
|Calibration||0 psia to full scale pressure||+1 to +32 2||+1 to +32 2||2.6 - 6 plus zero conductivity (air) 2|
|Repeatability||0.005% of full scale|
|Hysteresis||0.005% of full scale|
¹ Digiquartz residual temperature sensitivity is
measured at Sea-Bird, and Digiquartz calibration coefficients are adjusted so
that residual temperature sensitivity is less than 1 ppm over 0 – 20 °C (0.05
ppm/°C; 0.0005 psia for a 10,000 psia range sensor).
Counter Time Base
(pressure and pressure temperature)
Quartz TCXO ± 3 ppm per year aging (± 1 ppm/year typical),
± 0.1 ppm (0 - 20 °C)
Ovenized Crystal Oscillator
(reference frequency drift correction)
Warm-up re-stabilization: less than ± 1 x 10 -7
Stability vs. temperature: ± 0.1 ppm (-20 °C to +70 °C)
Aging: < 1 x 10 -7 per year, less than 1 x 10 -6 /10 years
(time stamp and sample timing)
Quartz TCXO watch-crystal type 32,768 Hz;
accuracy ± 2 ppm (5 seconds/month).
Battery-backed for minimum 2-year operation without main batteries installed.
|Conductivity Time Base||
Quartz TCXO ± 1 ppm per year aging;
± 15 ppm (-20 to +70 °C).
Memory: 32 Mbyte Flash RAM
Data Storage (per sample):
No conductivity: 17 bytes/sample
With conductivity: 20 bytes/sample
Internal: 12 alkaline D-cells, Duracell MN 1300, LR20 (standard) or 6 lithium DD-cells (Electrochem BCX85-3B76-TC)
External: 12 - 24 VDC nominal
Housing: Titanium to 7000 meters
Weight (with alkaline batteries): 14.5 kg (32 lbs) in air; 8.6 kg (19 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.