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BPR Bottom Pressure Recorder
SBE 53

Print version     Current manual (older manuals)     Configuration options & accessories

SBE 53 BPR Bottom Pressure Recorder

SUMMARY

DESCRIPTION

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:

 Options include:

SOFTWARE

The BPR includes Seasoft© for Waves, a comprehensive package of Windows programs for instrument setup and data retrieval, data conversion, and plotting.

SPECIFICATIONS

  Pressure Standard Temperature (°C) High Accuracy Temperature (°C) optional Conductivity (S/m)  optional
Measurement Range 0 to 1300, 2000, 4000, or 6800 m
(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).
2 Measurements outside specified calibration ranges at slightly reduced accuracy due to extrapolation errors.

Clocks:

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
Real-Time Clock
(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

Power Supply:
   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.

Software

Links to Other Instruments of Interest

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Specifications are subject to change without notice.

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