The SBE 53 BPR measures full ocean depth water level with extremely high resolution, accuracy, and stability. It 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.
The BPR integrates pressure measurements to obtain water levels (tides) unaffected by wave action. The interval between each water level measurement is programmable (1 minute to 1 hour), and the integration duration is also programmable (1 minute to 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, it can enter a power-down state between measurements to conserve battery power, with a user-specified warm-up period before each pressure measurement. Temperature data is recorded with each pressure integration. Logging start and stop times are programmable, allowing lab setup before deployment.
The BPR stores data in memory, and also outputs real-time data. The large memory and low power requirements permit frequent water level recording. An input connector for an optional SBE 4M conductivity sensor is standard.
- Full ocean depth water level (6800 m), with extremely high resolution, accuracy, and stability.
- Precision thermometer, optional conductivity sensor.
- RS-232 interface, internal memory, and internal alkaline batteries (can be powered externally).
- Real-time data, and fast upload binary upload of data from memory
- Large memory and low power requirements: 1.2-year deployment with alkaline batteries for a typical sampling scheme of water level measurements every 30 minutes (integrating pressure for the entire 30 minutes).
- Seasoft© for Waves Windows software package (setup, data upload, data conversion, plotting).
- Five-year limited warranty.
- Paroscientific Digiquartz® temperature-compensated pressure sensor, in four ranges from 1300 - 6800 m (2000 - 10,000 psia).
- Aged and pressure-protected thermistor with a long history of exceptional accuracy and stability.
- Frequency-input channel and bulkhead connector for optional SBE 4M conductivity sensor.
- Measurement times set by a continuously powered, real-time clock (accuracy ±5 sec/month). Long-term drift of counter’s reference frequency approximately 1 ppm/year. To allow for drift correction, ovenized crystal oscillator is programmed to periodically make a reference frequency measurement.
- Accurate temperature sensor (aged thermistor embedded in end cap) or high-accuracy external temperature sensor.
- XSG/AG or wet-pluggable MCBH connectors.
- SBE 4M Conductivity sensor, interfaced via bulkhead connector and clamped to housing.
- Mounting fixture.
- Lithium batteries (not supplied by Sea-Bird).
|Pressure||0 to 1300, 2000, 4000, or 6800 m (2000, 3000, 6000, or 10,000 psia)|
|Temperature||-5 to +35 °C (embedded or high-accuracy external)|
|Conductivity (optional)||0 to 7 S/m|
|Pressure *||± 0.01% of full scale|
|Temperature||± 0.01 °C (embedded); ± 0.002 °C (high-accuracy external)|
|Conductivity (optional)||± 0.001 S/m|
* Digiquartz residual temperature sensitivity is measured at Sea-Bird, and Digiquartz calibration coefficients are adjusted so that residual temperature sensitivity < 1 ppm over 0 – 20 °C (0.05 ppm/°C; 0.0005 psia for 10,000 psia range sensor).
|Pressure||0.005% of full scale|
|Pressure||0.045 ppm (0.3 mm for 10,000 psia range, 1-min integration, continuously powered)|
|Temperature||0.001 °C (embedded); 0.0001 °C (high-accuracy external)|
|Conductivity (optional)||0.00002 S/m|
|Pressure||0.005% of full scale|
|Clocks||Counter Time Base (pressure, 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: < ± 1 x 10 -7;
Stability vs. temperature: ± 0.1 ppm (-20 to +70 °C); Aging: < 1 x 10 -7 per year, < 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 sec/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 & Data Storage||32 Mbyte non-volatile Flash;
No conductivity: 17 bytes/sample; With conductivity: 20 bytes/sample
|Power Supply||12 alkaline D-cells or 6 lithium DD-cells (see manual for battery specifications and endurance)|
|Optional External Power||12 - 24 VDC|
|Housing, Depth Rating, & Weight||Titanium, 7000 m, in air 14.5 kg; in water 8.6 kg
Mounting fixture weight in air 3.6 kg; in water 1.4 kg
Do I need to remove batteries before shipping my instrument for a deployment or to Sea-Bird?
Alkaline batteries can be shipped installed in the instrument. See Shipping Batteries for information on shipping instruments with Lithium or Nickel-Metal Hydride (NiMH) batteries.
What are the recommended practices for connectors - mating and unmating, cleaning corrosion, and replacing?
Mating and Unmating Connectors:
It is important to prepare and mate connectors correctly, both in terms of the costs to repair them and to preserve data quality. Leaking connectors cause noisy data and even potential system shutdowns. Application Note 57: Connector Care and Cable Installation describes the proper care and installation of connectors for Sea-Bird instruments. The Application Note covers connector cleaning and cable or dummy plug installation, locking sleeve installation, and cold weather tips.
Checking for Leakage and Cleaning Corrosion on Connectors:
If there has been leakage, it will show up as green-colored corrosion product. Performing the following steps can usually reverse the effect of the leak:
- Thoroughly clean the connector with water, followed by alcohol.
- Give the connector surfaces a light coating of silicon grease.
Re-mate the connectors properly — see Application Note 57: Connector Care and Cable Installation and 9-minute video covering O-ring, connector, and cable maintenance.
- The main concern when replacing a bulkhead connector is that the o-rings on the connector and end cap must be prepared and installed correctly; if they are not, the instrument will flood. See the question below for general procedure on handling o-rings.
- Use a thread-locking compound on the connector threads to prevent the new connector from loosening, which could also lead to flooding.
- If the cell guard must be removed to open the instrument, take extra care not to break the glass conductivity cell.
Can I use a pressure sensor above its rated pressure?
Digiquartz pressure sensors are used in the SBE 9plus, 53, and 54. The SBE 16plus V2, 16plus-IM V2, 19plus V2, and 26plus can be equipped with either a Druck pressure sensor or a Digiquartz pressure sensor. All other instruments that include pressure use a Druck pressure sensor.
- The overpressure rating for a Digiquartz (as stated by Paroscientific) is 1.2 * full scale. The sensor will provide data values above 100% of rated full scale; however, Sea-Bird does not calibrate beyond the rated full scale.
- The overpressure rating for a Druck (as stated by Druck) is 1.5 * full scale. The sensor will provide data values above 100% of rated full scale; however, Sea-Bird does not calibrate beyond the rated full scale.
Note: If you use the instrument above the rated range, you do so at your own risk; the product will not be covered under warranty.
What is the maximum cable length for real-time RS-232 data?
Cable length is one of the most misunderstood items in the RS-232 world. The RS-232 standard was originally developed decades ago for a 19200 baud rate, and defines the maximum cable length as 50 feet, or the cable length equal to a capacitance of 2500 pF. The capacitance rule is often forgotten; using a cable with low capacitance allows you to span longer distances without going beyond the limitations of the standard. Also, the maximum cable length mentioned in the standard is based on 19200 baud rate; if baud is reduced by a factor of 2 or 4, the maximum length increases dramatically. Using typical underwater cables, allowable combinations of cable length and baud rate for Sea-Bird instruments communicating with RS-232 are shown below:
|Maximum Cable Length (meters)||Maximum Baud Rate*|
*Note: Consult instrument manual for baud rates supported for your instrument.
Do you recommend a particular brand of alkaline D-cell batteries?
For Sea-Bird instruments that use alkaline D-cells, Sea-Bird uses Duracell MN 1300, LR20. While rare, we have seen a few problems with cheaper batteries over the years: they are more likely to leak, may vary in size (leading to loose batteries causing a bad power connection), and may not last as long.
How should I pick the pressure sensor range for my CTD? Would the highest range give me the most flexibility in using the CTD?
While the highest range does give you the most flexibility in using the CTD, it is at the expense of accuracy and resolution. It is advantageous to use the lowest range pressure sensor compatible with your intended maximum operating depth, because accuracy and resolution are proportional to the pressure sensor's full scale range. For example, the SBE 9plus pressure sensor has initial accuracy of 0.015% of full scale, and resolution of 0.001% of full scale. Comparing a 2000 psia (1400 meter) and 6000 psia (4200 meter) pressure sensor:
- 1400 meter pressure sensor ‑ initial accuracy is 0.21 meters and resolution is 0.014 meters
- 4200 meter pressure sensor ‑ initial accuracy is 0.63 meters and resolution is 0.042 meters
How often do I need to have my instrument and/or auxiliary sensors recalibrated? Can I recalibrate them myself?
- Profiling CTD — recalibrate once/year, but possibly less often if used only occasionally. We recommend that you return the CTD to Sea-Bird for recalibration. (In principle, it is possible for calibration to be performed elsewhere, if the calibration facility has the appropriate equipment andtraining. However, the necessary equipment is quite expensive to buy and maintain.) In between laboratory calibrations, take field salinity samples to document conductivity cell drift.
- Thermosalinograph — recalibrate at least once/year, but possibly more often depending on the degree of bio-fouling in the water.
- DO sensor —
— SBE 43 — recalibrate once/year, but possibly less often if used only occasionally and stored correctly (see Application Note 64), and also depending on the amount of fouling and your ability to do some simple validations (see Application Note 64-2)
— SBE 63 — recalibrate once/year, but possibly less often if used only occasionally and stored correctly and also depending on the amount of fouling and your ability to do some simple validations (see SBE 63 manual)
- pH sensor —
— SBE 18 pH sensor or SBE 27 pH/ORP sensor — recalibrate at the start of every cruise, and then at least once/month, depending on use and storage
— Satlantic SeaFET pH sensor — recalibrate at least once/year. See FAQ tab on Satlantic's SeaFET page for details (How often does the SeaFET need to be calibrated?).
- Transmissometer — usually do not require recalibration for several years. Recalibration at the manufacturer’s factory is the most practical method.
We often have requests from customers to have some way to know if the CTD is out of calibration. The general character of sensor drift in Sea-Bird conductivity, temperature, and pressure measurements is well known and predictable. However, it is very difficult to know precisely how far a CTD calibration has drifted over time unless you have access to a very sophisticated calibration lab. In our experience, an annual calibration schedule will usually maintain the CTD accuracy to within 0.01 psu in Salinity.
Conductivity drifts as a change in slope as a result of accumulated fouling that coats the inside of the conductivity cell, reducing the area of the cell and causing an under-reporting of conductivity. Fouling consists of both biological growth and accumulated oils and inorganic material (sediment). Approximately 95% of fouling occurs as the cell passes through oil and other contaminants floating on the sea surface. Most conductivity fouling is episodic, as opposed to gradual and steady drift. Most fouling events are small and mostly transitory, but they have a cumulative affect over time. A severe fouling event, such as deployment through an oil spill, could have a dramatic but only partially recoverable effect, causing an immediate jump shift toward lower salinity. As fouling becomes more severe, the fit becomes increasingly non-linear and offsets and slopes no longer produce adequate correction, and return to Sea-Bird for factory calibration is required. Frequently checking conductivity drift is likely to be the most productive data assurance measure you can take. Comparing conductivity from profile to profile (as a routine check) will allow you to detect sudden changes that may indicate a fouling event and the need for cleaning and/or re-calibration.
Temperature generally drifts slowly, at a steady rate and predictably as a simple offset at the rate of about 1-2 millidegrees per year. This is approximately equal to 1-2 parts per million in Salinity error (very small).
Pressure sensor drift is also an offset, and annual comparisons to an accurate barometer to determine offset will generally keep the sensor within specification for several years, particularly as the sensors age over time.
|Family||.||Housing||Pressure Sensor/Range||Connectors||Temperature Sensor|
|53||.||3 – 7000 m (titanium)||G – 2000 psia Digiquartz||1 – XSG/AG||1 – Internal|
|H – 3000 psia Digiquartz||2 – MCBH||2 – External|
|I – 6000 psia Digiquartz|
|J – 10,000 psia Digiquartz|
Example: 53.3G21 is an SBE 53 with 7000 m housing, 2000 psia Digiquartz pressure sensor, MCBH connectors, & internal temperature sensor. See table below for description of each selection:
Bottom Pressure Recorder - With high pressure range quartz crystal pressure sensor, built-in temperature sensor, 7000 m titanium pressure housing with battery compartment for
For depths less than 680 m, use SBE 26plus.
|SBE 53 BPR Pressure Sensor Range (approximate maximum depth) Selections — MUST SELECT ONE|
|53.3Gxx||10,000 psia (6800 m) Digiquartz pressure sensor||Pressure sensor is installed in connector end cap, & is not field-replaceable / swappable. While highest depth rating gives most flexibility in using SBE 53, it is at expense of accuracy & resolution. It is advantageous to use lowest range pressure sensor compatible with your intended maximum operating depth, because accuracy & resolution are proportional to sensor's full scale range. For example, comparing 2000 psia (1300 m) & 10,000 psia (6800 m) sensors:
|53.3Hxx||6000 psia (4000 m) Digiquartz pressure sensor|
|53.3Ixx||3000 psia (2000 m) Digiquartz pressure sensor|
|53.3Jxx||2000 psia (1300 m) Digiquartz pressure sensor|
|SBE 53 BPR Connector Selections— MUST SELECT ONE|
|53.3x1x||XSG/AG connectors on instrument & data I/O cable||Wet-pluggable connectors may be mated in wet conditions. Their pins do not need to be dried before mating. By design, water on connector pins is forced out as connector is mated. However, they must not be mated or un-mated while submerged. Wet-pluggable connectors have a non-conducting guide pin to assist pin alignment & require less force to mate, making them easier to mate reliably under dark or cold conditions, compared to XSG/AG connectors. Like XSG/AG connectors, wet-pluggables need proper lubrication & require care during use to avoid trapping water in sockets.
|53.3x2x||Wet-pluggable (MCBH) connectors on instrument & data I/O cable|
|SBE 53 BPR Temperature Sensor Selections— MUST SELECT ONE|
|53.3xx1||Accurate (0.01 C) internal thermistor||
Internal thermistor has 0.01 °C accuracy, 0.001 °C resolution.
High accuracy external thermistor has 0.002 °C accuracy, 0.0001 °C resolution.
|53.3xx2||High accuracy (0.002 C) external thermistor probe|
|SBE 53 BPR Conductivity Sensor Options|
|53-3a||Conductivity sensor (SBE 4M, titanium housing, XSG connector on SBE 4, 53, & cable) - includes cable & mount, anti-foul holders & AF24173 anti-foulant devices||
SBE 4M is shipped with Tygon tubing looped end-to-end around conductivity cell, to prevent dust & dirt from entering cell. SBE 4M is shipped dry to prevent conductivity cell damage from freezing.
|53-3c||Conductivity sensor (SBE 4M, titanium housing, MCBH connector on SBE 4, 53, & cable) - includes cable & mount, anti-foul holders & AF24173 anti-foulant devices|
|53-3b||Delete Anti foulant holder & AF24173 from conductivity sensor option 53-3a (CREDIT)||
When included with SBE 53, SBE 4M includes a 50315 fitting on each end to hold an AF24173 Anti-Foulant Device. If you are deploying SBE 53 in an area where you do not think conductivity cell fouling will be a problem, you may delete fittings & anti-foulant devices for credit.
|SBE 53 BPR Spares & Accessories|
|801225||Data I/O cable, RMG-4FS w/ DB-9S, 2.4 m (DN 32421)||These test cables are used for setting up system & uploading data from memory after recovery. Applicable cable is included with SBE 53; listing here is for spare cable.|
|801374||Data I/O cable, Wet-pluggable (MCIL-4FS) w/ DB-9S, 2.4 m (DN 32715)|
|20200||USB to Serial Port Adapter, FTDI UC232R-10 (connects computers with USB ports to RS-232 instruments)||Many newer PCs & laptop computers have USB port(s) instead of RS-232 serial port(s). USB serial adapter plugs into USB port, & allows a serial device to be connected through adapter. Multi-port adapters are available from other companies; see Application Note 68.|
|801542||AF24173 Anti-Foulant Device pair (spare, bagged, labeled for shipping)||
50315 provides fittings (2) to hold AF24173 Anti-Foulant Devices at each end of optional SBE 4M conductivity cell. See Application Note 70: Installing Anti-Foulant Device Mount Kit on SBE 4, 16, 19, and 21 Conductivity Cells.
|50315||Anti-foul holder kit - installs on SBE 4M to allow use of AF24173 in place of obsolete 24012 Anti-Foulant Devices. Order AF24173 separately.|
|50286||SBE 4 mounting bracket for SBE 26/26plus/53||Mount bracket included if SBE 53 is ordered with SBE 4M; this is spare.|
|17695||SBE 4 to SBE 26/26plus/53 interface cable, RMG-3FS to RMG-3FS, 0.3 m (DN 30566)||17695 included if SBE 53 is ordered with SBE 4M with XSG connector; this is spare.
171752 included if SBE 53 is ordered with SBE 4M & wet-pluggable connector; this is spare.
|171752||SBE 4 to SBE 26/26plus/53 interface cable, Wet-pluggable (MCIL-3FS to MCIL-3FS), 0.3 m (DN 32671)|
|801575||Battery Cover Spacer / Adapter, 12 D alkaline cells to 6 DD Electrochem Lithium cells||Battery cover spacer/adapter is required if using DD lithiums (six DD drop-in batteries with buttons), because 1 lithium DD battery is shorter than 2 alkaline D batteries.
Note: Sea-Bird does not supply Electrochem lithium batteries; you must purchase them elsewhere (see WGT's website for purchasing information). Shipping restrictions apply for Electrochem lithium batteries & assembled battery packs.
Many cables, mount kits, and spare parts can be ordered online.
- 801225 To computer COM port (from XSG connector), 2.4 m, DN 32421
- 801374 To computer COM port (from Wet-pluggable connector), 2.4 m, DN 32715
- 17695 To SBE 4 (from XSG connector), 0.28 m, DN 30566
- 171752 To SBE 4 (from Wet-pluggable connector), 0.28 m, DN 32671
- 50092 Jackscrew kit for SBE 16, 17plus, 19, 21, 25, 26/26plus, 52-MP, 53, 54, AFM, or PDIM
- 60021 Battery end cap hardware & O-ring kit for SBE 16/16plus/16plus-IM/16plus V2/16plus-IM V2, 17plus, 19/19plus/19plus V2, 25, 26/26plus, 53, 54, 55, or AFM (document 67042)
- 50056 Hardware kit for SBE 26/26plus, 53, or 54 (document 67016)
- 801542 AF24173 Anti-Foulant Device (pair, bagged, labeled for shipping)
- 50315 Anti-foul holder kit (for SBE 4 Conductivity Sensor) — installs on SBE 4 & SeaCATs (not SeaCATplus) to allow use of AF24173 in place of obsolete 24012 Anti-Foulant Devices. Order AF24173 separately. (see Application Note 70)
- 801575 Battery Cover Spacer / Adapter, 12 D alkaline cells to 6 DD Electrochem Lithium cells
Compare Moored / Time Series Recording Instruments
(C, T, P)
|SBE 16plus V2 SeaCAT C-T (P) Recorder||C, T, P*||6 A/D; 1 RS-232||64 Mb||RS-232||Optional pump|
|SBE 16plus SeaCAT C-T (P) Recorder
||C, T, P*||4 A/D; optional RS-232 or PAR||8 Mb||RS-232 or -485||Replaced by SBE 16plus V2 in 2008|
|SBE 16 SeaCAT C-T (P) Recorder
||C, T, P*||4 A/D||1 Mb||RS-232||Replaced by SBE 16plus in 2001|
|SBE 16plus-IM V2 SeaCAT C-T (P) Recorder||C, T, P*||6 A/D; 1 RS-232||64 Mb||Inductive Modem||Optional pump|
|SBE 16plus-IM SeaCAT C-T (P) Recorder
||C, T, P*||4 A/D; optional RS-232 or PAR||8 Mb||Inductive Modem||Replaced by SBE 16plus-IM V2 in 2008|
|SBE 19plus V2 SeaCAT Profiler CTD||C, T, P||6 A/D;
|64 Mb||RS-232||Programmable mode — profiling or moored|
|SBE 19plus SeaCAT Profiler CTD
||C, T, P||4 A/D; optional PAR||8 Mb||RS-232||Replaced by SBE 19plus V2 in 2008|
|SBE 19 SeaCAT Profiler CTD
||C, T, P||4 A/D||1 - 8 Mb||RS-232||Replaced by SBE 19plus in 2001|
|SBE 37-SM MicroCAT C-T (P) Recorder||C, T, P*||8 Mb||RS-232 or -485|
|SBE 37-SMP MicroCAT C-T (P) Recorder||C, T, P*||8 Mb||RS-232, RS-485, or SDI-12||Integral pump|
|SBE 37-SMP-IDO MicroCAT C-T-DO (P) Recorder||C, T, P*||Integrated DO||8 Mb||RS-232 or -485||Integral pump; Replaced by SBE 37-SMP-ODO in 2014|
|SBE 37-SMP-ODO MicroCAT C-T-DO (P) Recorder||C, T, P*||Integrated Optical DO||8 Mb||RS-232, RS-485, or SDI-12||Integral pump|
|SBE 37-IM MicroCAT C-T (P) Recorder||C, T, P*||8 Mb||Inductive modem|
|SBE 37-IMP MicroCAT C-T (P) Recorder||C, T, P*||8 Mb||Inductive modem||Integral pump|
|SBE 37-IMP-IDO MicroCAT C-T-DO (P) Recorder||C, T, P*||Integrated DO||8 Mb||Inductive modem||Integral pump; Replaced by SBE 37-IMP-ODO in 2014|
|SBE 37-IMP-ODO MicroCAT C-T-DO (P) Recorder||C, T, P*||Integrated Optical DO||8 Mb||Inductive modem||Integral pump|
|SBE 37-SI MicroCAT C-T (P) Recorder||C, T, P*||8 Mb||RS-232 or -485|
|SBE 37-SIP MicroCAT C-T (P) Recorder||C, T, P*||8 Mb||RS-232 or -485||Integral pump|
|C, T, P*||Integrated DO||8 Mb||RS-232 or -485||Integral pump|
|SBE 39plus Temperature (P) Recorder||T, P*||64 Mb||Optional||USB & RS-232||Optional|
|SBE 39 Temperature (P) Recorder
||T, P*||32 Mb||Optional||RS-232||Optional||Replaced by SBE 39plus in 2014|
|SBE 39plus-IM Temperature (P) Recorder||T, P*||64 Mb||Inductive Modem & USB|
|SBE 39-IM Temperature (P) Recorder||T, P*||32 Mb||Inductive modem||Replaced by SBE 39plus-IM in 2016|
|SBE 56 Temperature Logger||T||64 Mb||USB|
|SBE 26plus Seagauge Wave & Tide Recorder||T, P||C optional||32 Mb||RS-232||
(tides, waves, & wave statistics)
|Wave & tide recorder|
|SBE 26 Seagauge Wave & Tide Recorder
||T, P||C optional||8 Mb||RS-232||Replaced by SBE 26plus in 2004|
|SBE 53 BPR Bottom Pressure Recorder||T, P||C optional||32 Mb||RS-232||Bottom pressure recorder|
|SBE 54 Tsunameter Tsunami Pressure Sensor||T, P||128 Mb||Optional||RS-232||Tsunami pressure sensor|
C = conductivity, T = temperature, P = pressure, DO = dissolved oxygen