SBE 54 Tsunameter Tsunami Pressure Sensor
The SBE 54 continuously measures, records, and outputs pressure at user-programmable periods. Resolution is better than 1 mm at full ocean depth (6800 m) at the default 15-second sample period. The SBE 54’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. Low power consumption makes multi-year, battery-powered deployments practical. The FLASH memory provides four years continuous backup of the raw pressure record, at a 15-second sample period. Preserving the entire time series in memory allows post-deployment review of the performance, as well as scientific analysis of the entire record. The EEPROM stores calibration coefficients and diagnostic information. The Digiquartz pressure sensor and frequency reference are tested and re-characterized at Sea-Bird to meet the demanding millimeter-scale sensitivity requirements.
- Full ocean depth pressure (6800 m), with extremely high resolution (> 1 mm resolution at 15-sec sample period).
- RS-232 interface.
- Internal memory and simple, XML, real-time data.
- Powered externally (short version) or internal batteries (long version).
- Large memory and low power consumption for multi-year deployments.
- Seasoft© for Waves Windows software package (setup, data upload, data conversion).
- Five-year limited warranty.
- Paroscientific Digiquartz® temperature-compensated pressure sensor, in four ranges from 1300 - 6800 m (2000 - 10,000 psia).
- Microcontroller, real-time clock with temperature-compensated crystal oscillator, precision temperature-compensated reference frequency, two high-resolution frequency acquisition circuits.
- Reference frequency that acquires pressure and pressure temperature outputs from pressure sensor accurate to 1 ppm and temperature calibrated to 50 ppb.
- Pressure sensor, reference frequency, and acquisition circuits powered continuously to eliminate start-up transient errors.
- Pressure and pressure temperature acquired simultaneously to eliminate phasing errors and increase measurement resolution.
- Short housing (externally powered), or
Long housing with battery compartment for 12 D cells (LR-20 – Alkaline) or 6 DD Lithium cells (internal battery diode or’ed with external supply for backup to external power).
- XSG/AG or wet-pluggable MCBH connector.
- Lithium batteries (not supplied by Sea-Bird).
|Measurement Range||0 to 1300, 2000, 4000, or 6800 m (2000, 3000, 6000, or 10,000 psia)|
|Resolution *||1.1 x 10 -7 of Digiquartz pressure range at default 15-sec sample period
(0.0011 psia [0.8 mm] with 10,000 psia sensor)
|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)|
|Data Output||Real-time pressure in ASCII engineering units (dbar, psia) at user-input sample period (1 - 240 sec; default 15 sec)|
|Memory||8.9 million samples (51 months at default 15-sec sample period)|
* Sum of all uncertainties in measurement of pressure change < 1 mm over a duration of a few minutes and < 5 mm over a duration of minutes to hours, including ocean/instrument temperature changes of 0.25° C.
|External Power||12 – 28 VDC|
|Power Consumption||0.015 Watt at 15V, 0.016 Watt at 20V, 0.0018 Watt at 24V, 0.022 Watt at 28V (running continuously)|
|Battery Endurance||12 Alkaline D cells: 14 months (80% capacity);
6 Lithium DD cells: 37 months (80% capacity)
|Housing & Depth Rating||Titanium, 7000 m|
|Weight||With long housing and alkaline batteries: in air 14.5 kg, in water 8.6 kg|
|Title||Type||Publication Date||PDF File|
|SBE 54 Brochure||Product Brochure||Monday, August 24, 2015||54BrochureAug15.pdf|
|SBE 54 Manual||Product Manual||Wednesday, February 18, 2015||54_008.pdf|
|Field Service Bulletin 13: Jackscrew Replacements||Field Service Bulletins||Monday, March 8, 2010||FSB13.pdf|
|AN57: Connector Care and Cable Installation||Application Notes||Tuesday, May 13, 2014||appnote57Jan14.pdf|
|AN68: Using USB Ports to Communicate with Sea-Bird Instruments||Application Notes||Friday, October 19, 2012||appnote68Oct12.pdf|
|AN71: Desiccant Use and Regeneration (drying)||Application Notes||Wednesday, May 18, 2016||Appnote71May16.pdf|
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.
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.
|Family||.||Housing||Pressure Sensor/Range||Connectors||Temperature Sensor|
|54||.||3 – 7000 m (titanium), long housing (batteries)||G – 2000 psia Digiquartz||1 – XSG/AG||0 – None|
|4 – 7000 m (titanium), short housing (no batteries)||H – 3000 psia Digiquartz||2 – MCBH|
|I – 6000 psia Digiquartz|
|J – 10,000 psia Digiquartz|
Example: 54.3J20 is an SBE 53 with 7000 m long housing, 10,000 psia Digiquartz pressure sensor, & MCBH connectors. See table below for description of each selection:
Tsunameter (Tsunami pressure sensor) - Includes Digiquartz pressure sensor, 128 MB Flash memory, titanium housing for 7000 m depth, RS-232 serial interface, 2.4 m data I/O cable (801385), software, & complete documentation.
SBE 54 continuously measures & outputs pressure every 15 seconds, with a pressure resolution of better than 1 mm at full ocean depth (7000 m). Its sole purpose is to function as heart of a deep ocean tsunami detection system. Standard SBE 54 is externally powered.
|SBE 54 Housing Selections — MUST SELECT ONE|
|54.3xx0||Long housing with battery compartment for 12 D (LR-20) cells||Short housing SBE 54 is externally powered. Long housing provides a battery compartment for 12 D alkaline cells (LR-20) or 6 DD Electrochem lithium cells (drop-in batteries with buttons); internal battery is diode or'ed with external supply for use as backup to external power supply.
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.
|54.4xx0||Short housing, no battery compartment (externally powered)|
|SBE 54 Pressure Sensor Range (approximate maximum depth) Selections — MUST SELECT ONE|
|54.xGx0||2000 psia (1300 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 54, 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:
|54.xHx0||3000 psia (2000 m) Digiquartz pressure sensor|
|54.xIx0||6000 psia (4000 m) Digiquartz pressure sensor|
|54.xJx0||10,000 psia (6800 m) Digiquartz pressure sensor|
|SBE 54 Connector Selections — MUST SELECT ONE|
|54.xx10||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.
|54.xx20||Wet-pluggable (MCBH) connectors on instrument & data I/O cable|
|SBE 54 Spares & Accessories|
|801385||Data/Power cable (SBE 54 with no battery compartment), RMG-4FS to DB-9S & red/black twisted wire leads, 2.4 m (DN 32277)||
These test cables are used for setting up system & uploading data from memory after recovery.
|801206||Data/Power cable (SBE 54 with no battery compartment), Wet-pluggable, MCIL-4FS to DB-9S & red/black twisted wire leads, 2.4 m (DN 32366)|
|801225||Data I/O cable (SBE 54 with battery), RMG-4FS w/ DB-9S, 2.4 m (DN 32421)|
|801374||Data I/O cable (SBE 54 with battery), Wet-pluggable (MCIL-4FS) w/ DB-9S, 2.4 m (DN 32715)|
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
- 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)
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