SBE 26plus Seagauge Wave and Tide Recorder

SBE 26plus Seagauge Wave & Tide Recorder

Wave and Tide, Temperature, and optional Conductivity data, with internal memory and batteries and real-time tide and wave data.

SUMMARY

  • Wave and Tide, Temperature, and (optional) Conductivity data
  • RS-232 (optional RS-485) serial interface, internal memory, internal batteries
  • Real-time tide data, wave data, and/or wave statistics, as well as fast upload of all data in memory upon recovery
  • Large memory and low power requirements: 1.8-year deployment with alkaline batteries for a typical sampling scheme (with optional conductivity) of 11-minute tide measurements every 30 minutes and 8.5-minute, 4 Hz wave-burst samples eight times a day.
  • Five-year limited warranty.

DESCRIPTION

The 26plus combines Sea-Bird's non-volatile FLASH memory with a stable time base, precision thermometer, and Quartz crystal pressure sensor to provide wave and tide recording of unprecedented resolution and accuracy, along with high-quality temperature information. An input connector for an optional SBE 4M conductivity sensor is standard.

The 26plus integrates pressure samples to obtain water level measurements unaffected by wave action, and also independently burst-samples pressure at rates up to 4 Hz for wave amplitude calculation. Water level and wave burst sampling intervals and durations are programmable. The tide interval is programmable from 1 minute to 12 hours. The 26plus can continuously measure pressure (with Quartz pressure sensor), or can conserve battery power by removing power from the pressure sensor between tide measurements, with programmable pressure integration from 10 seconds to the entire tide interval. Temperature data is recorded with each tide integration. Waves are characterized by burst sampling, with programmable burst interval, number of samples per burst, and burst integration time. Logging start and stop times are programmable, allowing complete setup in the lab before deployment.

The large memory and low power requirements permit frequent water level recording and highly detailed wave characterization. For example, with Quartz pressure sensor, standard alkaline batteries, and optional conductivity sensor, a 445-day deployment can include water level measurements every 30 minutes (integrating pressure for the entire 30 minutes) and an 8.5-minute, 4 Hz wave-burst (2048 samples) eight times a day; a 670-day deployment can be achieved if pressure integration is limited to 11 minutes for each water level measurement.

The 26plus stores data in memory, and also outputs real-time tide data, wave data, and/or wave statistics. Binary upload capability at 115,200 baud allows for fast upload of data in memory upon recovery. Firmware upgrades can be downloaded via the serial interface, without opening the instrument.

CONFIGURATION AND OPTIONS

A standard SBE 26plus is supplied with:

  • Plastic housing for depths to 600 meters (1960 feet), with Impulse glass-reinforced epoxy bulkhead connectors
  • 20 meter (45 psia) Digiquartz® temperature-compensated pressure sensor
  • Accurate temperature sensor – aged thermistor embedded in 26plus end cap
  • Frequency input channel and bulkhead connector for optional SBE 4M conductivity sensor
  • 32 MB FLASH memory, 12 alkaline D-cell batteries (Duracell MN1300, LR20)

Options include:

  • Digiquartz® temperature-compensated pressure sensor in ranges from 0.2 to 680 meters (15 to 1000 psia)
  • Lower priced temperature-compensated strain-gauge pressure sensor in ranges from 20 to 600 meters (45 to 880 psia), generally intended for wave sampling applications; will not provide highest quality tide data
  • SBE 4M Conductivity sensor, interfaced via bulkhead connector and clamped to 26plus housing
  • High accuracy external temperature sensor
  • RS-485 full duplex interface in place of standard RS-232 interface
  • Wet-pluggable (MCBH Micro) connectors in place of standard connectors
  • Mounting fixture

SOFTWARE

The SBE 26plus is supplied with Seasoft© for Waves, a comprehensive package of Windows programs including deployment planning, instrument setup and data retrieval, plotting, auto-spectrum and time series analysis, and statistics reporting.


Auto-spectrum plot of surface wind waves obtained from 1 burst sample of 1024 pressure measurements. Error bars correspond to 90% confidence intervals.

  Quartz Pressure
(standard)
Strain Gauge Pressure
(optional)
 Temperature (°C)
(standard)
High Accuracy Temperature (°C)
(optional)
Conductivity (S/m) 
(optional)
Measurement Range 9 ranges, from
0 - 0.2 m (15 psia) to 
0 - 680 m (1000 psia)
4 ranges, from
0 - 20 m (45 psia) to 
0 - 600 m (880 psia)
-5 to +35 -5 to +35 0 to 7
Accuracy ± 0.01% of full scale 
(3 mm for 45 psia range ¹)
± 0.1% of full scale 
(30 mm for 45 psia range ¹)
± 0.01 ± 0.002 ± 0.001
Resolution Tide:
0.2 mm (0.008 in.) for 
1-minute integration;
0.01 mm (0.0004 in.) for 
15-minute integration ¹
Tide:
0.2 mm (0.008 in.) for 
1-minute integration;
0.01 mm (0.0004 in.) for 
15-minute integration ¹
0.001 0.0001 0.00002
Wave:
0.4 mm (0.016 in.) for 
0.25-second integration;
0.1 mm (0.004 in.) for 
1-second integration ¹
Wave:
0.4 mm (0.016 in.) for 
0.25-second integration;
0.1 mm (0.004 in.) for 
1-second integration ¹
Calibration 0 psia to full scale pressure 0 psia to full scale pressure +1 to +32 2 +1 to +32 2 2.6 - 6 plus zero conductivity (air) 2
Stability 0.02% of full scale/year 
(6 mm for 45 psia range ¹)
0.1% of full scale/year
(30 mm for 45 psia range ¹)
     
Hysteresis 0.005% of full scale 
(1.5 mm for 45 psia range ¹)
0.03% of full scale 
(9 mm for 45 psia range ¹)
     
¹ Stated values in mm for 45 psia pressure sensor. Scale for other ranges, multiplying by (sensor psia / 45 psia).
2 Measurements outside the specified calibration ranges at slightly reduced accuracy due to extrapolation errors.

Real-time clock: 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.

Memory: 32 Mbyte Flash RAM

Data storage:
Tide with temperature and time: 9 bytes/sample
Tide with temperature, conductivity, and time: 12 bytes/sample
Wave burst: 3 bytes/sample

Power supply:
Internal: 12 alkaline D-cells, Duracell MN 1300, LR20 (standard) or 6 lithium DD-cells (Electrochem BCX85-3B76-TC)
External (optional): 12 - 20 VDC

Housing: Acetal copolymer plastic to 600 meters

Weight:
With alkaline batteries: 6.8 kg (15 lbs) in air; 2.3 kg (5 lbs) in water;
Mounting fixture: 3.6 kg (8 lbs) in air; 1.4 kg (3 lbs) in water

The list below includes (as applicable) the current product brochure, manual, and quick guide; software manual(s); and application notes.

For older SBE 26plus product manuals, organized by instrument firmware version, click here.

Title Type Publication Date PDF File
SBE 26plus Brochure Product Brochure Monday, April 22, 2013 26plusBrochureApr13.pdf
SBE 26plus Manual Product Manual Monday, April 22, 2013 26plus_018.pdf
AN02D: Instructions for Care and Cleaning of Conductivity Cells Application Notes Monday, March 10, 2014 appnote2DMar14.pdf
AN06: Determination of Sound Velocity from CTD Data Application Notes Tuesday, February 2, 2010 appnote06Aug04.pdf
AN10: Compressibility Compensation of Sea-Bird Conductivity Sensors Application Notes Tuesday, May 7, 2013 appnote10May13.pdf
AN14: 1978 Practical Salinity Scale Application Notes Thursday, January 12, 1989 appnote14.pdf
AN27D: Minimizing Strain Gauge Pressure Sensor Errors Application Notes Thursday, February 13, 2014 appnote27DFeb14.pdf
AN33: Using the DC Opto Isolated Junction Box [PN 91118] Application Notes Saturday, March 3, 2001 appnote33.pdf
AN42: ITS-90 Temperature Scale Application Notes Thursday, February 13, 2014 appnote42Feb14.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
AN69: Conversion of Pressure to Depth Application Notes Monday, July 1, 2002 appnote69.pdf
AN70: Installing Anti-Foulant Device Mount Kit on SBE 4, 16, 19, and 21 Conductivity Cells Application Notes Monday, May 19, 2008 appnote70May08.pdf
AN71: Desiccant Use and Regeneration (drying) Application Notes Wednesday, January 15, 2014 Appnote71Jan14.pdf
AN73: Using Instruments with Pressure Sensors at Elevations Above Sea Level Application Notes Friday, February 28, 2014 appnote73Feb14.pdf
AN83: Deployment of Moored Instruments Application Notes Friday, February 14, 2014 appnote83Feb14.pdf
Seasoft for Waves© is for use with the Seagauge Wave and Tide Recorder — SBE 26plus (current production) or SBE 26 (older version) — and the SBE 53 BPR Bottom Pressure Recorder.
Version 2.0 released September 8, 2011
SeasoftWaves_V2_0.exe for Windows XP/Vista/7


How should I handle my CTD to avoid cracking the conductivity cell?

Shipping: Sea-Bird carefully packs the CTD in foam for shipping. If you are shipping the CTD or conductivity sensor, carefully pack the instrument using the original crate and packing materials, or suitable substitutes.

Use: Cracks at the C-Duct end of the conductivity cell are most often caused by:

  • Hitting the bottom, which can cause the T-C Duct to flex, resulting in cracking at the end of the cell.
  • Removing the soaker tube from the T-C duct in a rough manner, which also causes the T-C Duct to flex. Pulling the soaker tube off at an angle can be especially damaging over time to the cell. Pull the soaker tube off straight down and gently.
  • Improper disassembly of the T-C ducted temperature and conductivity sensors (SBE 25, 25plus, and 9plus) when removing them for shipment to Sea-Bird for calibration. See Shipping SBE 9plus, 25, and 25plus Temperature and Conductivity Sensors for the correct procedure.

Note: If a Tygon tube attached to the conductivity cell has dried out, yellowed, or become difficult to remove, slice (with a razor knife or blade) and peel the tube off of the conductivity cell rather than twisting or pulling the tube off.

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?

General recommendations:

  • 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 — recalibrate every 6 months
  • Transmissometer — usually do not require recalibration for several years. Recalibration at the manufacturer’s factory is the most practical method.

Profiling CTDs:

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:

  1. Thoroughly clean the connector with water, followed by alcohol.
  2. 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.

Replacing Connectors:

  • 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.

What are the recommended practices for inspecting, cleaning, and replacing o-rings?

Inspecting and Cleaning O-Rings and Mating Surfaces:

  1. Remove any water from the o-rings and mating surfaces with a lint-free cloth or tissue.
  2. Visually inspect the o-rings and mating surfaces for dirt, nicks, cuts, scratches, lint, hair, and any signs of corrosion; these could cause the seal to fail. Clean the surfaces, and clean or replace the o-rings as necessary.
  3. Apply a light, even coat of 100% silicon o-ring lubricant (Parker Super O Lube) to the o-rings and mating surfaces. For an end cap o-ring, a ball of lubricant the size of a pea is about all that is needed. Too much lubricant can cause the seal to fail as much, if not more, than no grease. Do not use petroleum-based lubricant (car grease, Vaseline, etc.), as it will cause premature failure of the rubber.
    CAUTION: Parker makes another product, Parker O Lube, that is petroleum-based. Do not use this product; verify that you are using Parker Super O Lube.
  4. After lubricating the o-ring, immediately reassemble the end cap or connector, verifying that no hairs or lint have collected on the lubricated o-ring.

Replacing O-Rings:

  • End Cap O-Rings: We recommend scheduled replacement of end cap o-rings approximately every 3 years, to prevent leaks caused by normal o-ring wear.
  • Connector O-Rings: Replacing connector o-rings requires de-soldering and re-soldering the connector wires, which makes it a more difficult task. Therefore, we recommend replacement of connector o-rings when needed, not on a routine, scheduled basis.

Additional Information:

  • 9-minute video covering O-ring, connector, and cable maintenance.
  • Short, silent video of application of lubricant to o-ring.
  • Short, silent video of application of lubricant to o-ring mating surface (note the use of a plastic dental syringe — no sharp points to scratch the housing — to apply the lubricant).

What are the recommended practices for storing sensors at low temperatures, and deploying at low temperatures or in frazil or pancake ice?

General

Large numbers of Sea-Bird conductivity instruments have been used in Arctic and Antarctic programs.

Special accommodation to keep temperature, conductivity, oxygen, and optical sensors at or above 0 C is advised. Often, the CTD is brought inside protective doors between casts to achieve this.

Conductivity Cell

When freezing is possible, we recommend that the conductivity sensor be stored dry. Remove larger droplets of water by blowing through the cell. Do not use compressed air, which typically contains oil vapor. Attach a length of Tygon tubing to each end of the conductivity cell to close the cell ends. See Application Note 2D: Instructions for Care and Cleaning of Conductivity Cells for details.

There are several considerations to weigh when contemplating deployments at low temperatures in general, and in frazil or pancake ice:

  • Ensure that the instrument is at or above water temperature before it is deployed. If the cell gets colder than 0 to -2 ºC while on deck, when it enters the water a layer of ice forms inside the cell as the cell warms to ocean temperature. If ice forms inside the conductivity cell, measurements will be low of correct until the ice layer melts and disappears. Thin layers of ice will not hurt the conductivity cell, but repeated ice formation on the electrodes will degrade the conductivity calibration (at levels of 0.001 to 0.020 psu) and thicker layers of ice can lead to glass fracture and permanent damage of the cell.
  • For accurate measurements, keep ice out of the sensing region of the conductivity cell. The conductivity measurement involves determining the electrical resistance of the water inside the sensor. Ice is essentially a non-conductor. To the extent that ice displaces the water, the conductivity will register (very) misleadingly low. Some type of screening is necessary to keep ice out of the cell. This is relatively easy to arrange for the Sea-Bird conductivity cell, which is an electrode-type cell, because its sensing region is totally inside a long tube; plastic mesh could be positioned at each end and would have zero effect on accuracy and stability.

The above considerations apply to all known conductivity sensor types, whether electrode or inductive types. 

If deploying at low temperatures but no surface frazil or pancake ice is present, rinse the conductivity cell in one of the following salty solutions (salty water depresses the freezing point) to prevent freezing during deployment. But this does not mean you can store the cell in one of these solutions outside . . . it will freeze.

  • Solution of 1% Triton in sterile seawater (use 0.5-micron filtered seawater or boiled seawater),   or
  • Brine solution (distilled seawater or homemade salt solution that is higher than 35 psu in salinity).

Note that there is still a risk of forming ice inside the conductivity cell if deploying through frazil or pancake ice on the surface, if the freezing point of the salt water is the same as the water temperature. Therefore, we recommend that you deploy the conductivity cell in a dry state for these deployments.

Commercially available alcohol or glycol antifreezes contain trace amounts of oils that will coat the conductivity cell and the electrodes, causing a calibration shift, and consequently result in errors in the data. Do not use alcohol or glycol in the conductivity cell.

Temperature Sensor

In general, neither the accuracy of the temperature measurement nor the survival of the temperature sensor will be affected by ice.

Oxygen Sensor

For the SBE 43 and SBE 63 Dissolved Oxygen sensor, avoid prolonged exposure to freezing temperature, including during shipment. Do not store the with water (fresh or seawater), Triton solution, alcohol, or glycol in the plenum. The best precaution is to keep the sensor indoors or in some shelter out of the cold weather.

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.

How do instruments handle external power if internal batteries are installed?

Most Sea-Bird instruments that are designed to be powered internally or externally incorporate diode or'd circuitry, allowing only the voltage that has the greater potential to power the instrument. You can power the instrument externally without running down the internal batteries. This allows you to lab test using external power that has higher voltage than the internal batteries, and then deploy using internal power, knowing that the internal batteries are fresh.

For the SBE 25plus, if external power of 14 volts or higher is applied, the 25plus runs off of the external power, even if the main battery voltage is higher.

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.

PART # DESCRIPTION NOTES
26plus

SEAGAUGEplus Wave & Tide Recorder - With Digiquartz pressure sensor (45 psia standard; other ranges available), built-in temperature sensor, & 600 m plastic housing with battery compartment for 12 D cells. Includes 32 MB memory, RS-232 serial interface with ASCII real-time data output, frequency input channel for SBE 4M conductivity sensor, 2.5 m data I/O cable (801225), Seasoft for Waves software, & complete documentation. Specify: pressure sensor selection.
(for depths greater than 680 m, use SBE 53 BPR)

SBE 26plus is available with RS-485 interface in place of RS-232 interface; see RS-485 Serial Interface Option below.

SBE 26plus Pressure Sensor Range (approximate maximum depth) Selections — MUST SELECT ONE Quartz or Strain Gauge Sensor
26p-1b 45 psia (20 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 26plus, 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 45 psia (20 m) & 200 psia (130 m) sensors:
  • 45 psia sensor ‑
    initial accuracy is .003 m (= 0.01% * 45 psia * 0.689 m/psi)
  • 200 psia sensor ‑
    initial accuracy is 0.014 m (= 0.01% * 200 psia * 0.689 m/psi)
26p-1c 15 psia (1 m, for high altitude lake research) Digiquartz pressure sensor
26p-1d 23 psia (5 m) Digiquartz pressure sensor
26p-1e 30 psia (10 m) Digiquartz pressure sensor
26p-1f 100 psia (60 m) Digiquartz pressure sensor
26p-1g 200 psia (130 m) Digiquartz pressure sensor
26p-1h 300 psia (200 m) Digiquartz pressure sensor
26p-1i 400 psia (270 m) Digiquartz pressure sensor
26p-1j 1000 psia (680 m) Digiquartz pressure sensor (longer housing required)
SBE 26plus Substitute Strain Gauge Pressure Sensor Selections (excellent wave measurements with 20 m sensor, or low accuracy water level with other ranges) — MUST SELECT ONE Quartz or Strain Gauge Sensor
26p-2a 20 m (30 dbar absolute) Druck strain gauge instead of Digiquartz sensor (CREDIT) Comparing strain gauge to Quartz pressure sensor specifications:
  • Accuracy — 0.1% strain gauge vs. 0.01% Quartz
  • Repeatability — 0.03% strain gauge vs. 0.005% Quartz
  • Hysteresis — 0.03% strain gauge vs. 0.005% Quartz
  • Resolution — strain gauge & Quartz resolution are equal

Pressure sensor is installed in connector end cap, & is not field-replaceable / swappable. While highest depth rating gives most flexibility in using 26plus, 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 20 m (30 dbar absolute = 45 psia) & 100 m (110 dbar absolute = 600 psia) sensors:

  • 20 m (30 dbar absolute = 45 psia) sensor ‑
    initial accuracy is .03 m (= 0.1% * 45 psia * 0.689 m/psi)
  • 100 m (110 dbar absolute = 160 psia) sensor ‑
    initial accuracy is 0.11 m (= 0.1% * 160 psia * 0.689 m/psi)
26p-2b 100 m (110 dbar absolute) Druck strain gauge instead of Digiquartz sensor (not recommended for waves) (CREDIT)
26p-2c 350 m (350 dbar absolute) Druck strain gauge instead of Digiquartz sensor (not recommended for waves) (CREDIT)
26p-2d 600 m (600 dbar absolute) Druck strain gauge instead of Digiquartz sensor (not recommended for waves) (CREDIT)
SBE 26plus Conductivity Sensor Options
26p-3c Conductivity sensor (SBE 4M, titanium) - includes cable & mount, anti-foul holders & AF24173 anti-foulant devices

SBE 4M shown in aluminum housing;
titanium housing version similar
Standard 26plus supports input from optional SBE 4M conductivity sensor through 3-pin bulkhead connector. SBE 4M can be integrated with 26plus at our factory, or you can purchase SBE 4M, mount kit, cable, anti-foul holders, & AF24173 anti-foulant devices at a later date & perform integration yourself.

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.

26p-3d Delete Anti foulant holder & AF24173 from conductivity sensor option (CREDIT)

When included with a 26plus, SBE 4M includes a 50315 fitting on each end to hold an AF24173 Anti-Foulant Device. If you are deploying 26plus in an area where you do not think conductivity cell fouling will be a problem, you may delete fittings & anti-foulant devices for credit.

 
50315 fitting & anti-foulant device

SBE 26plus Wet-Pluggable Connector Options
26p-4a Wet-pluggable (MCBH) connectors instead of XSG/AG & RMG connectors on instrument & data I/O cable (conductivity sensor not installed)

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.
Both 26p-4 options include wet-pluggable bulkhead connectors on 26plus & data I/O cable compatible with wet-pluggable data I/O connector. 26p-4b also includes additional cost of wet-pluggable connector on SBE 4M, & SBE 4M cable with wet-pluggable connectors on both ends.

26p-4b Wet-pluggable (MCBH) connectors instead of XSG/AG & RMG connectors on instrument & data I/O cable (including on conductivity sensor)
SBE 26plus RS-485 Serial Interface Option
26p-5 RS-485 full duplex interface (6-pin connector) instead of RS-232 interface 26plus with RS-485 interface can transmit data over 1200 m of twisted pair wire cable (26 AWG or smaller gauge) at up to 38,400 baud. In comparison, 26plus with RS-232 interface can transmit data over 25 m of cable at 38,400 baud, 1600 m of cable at 600 baud (interpolate to determine maximum lengths for intermediate baud rates).
SBE 26plus High Accuracy External Temperature Interface Option
26p-5 High accuracy (0.002 C) external thermistor probe instead of standard internal thermistor High accuracy external thermistor has 0.002 °C accuracy, 0.0001 °C resolution. In comparison, standard internal thermistor has 0.01 °C accuracy, 0.001 °C resolution.
SBE 26plus Spares & Accessories
50102 Seagauge mounting fixture with mooring lock pin for quick installation & removal (without tools) from permanent deployment site Optional mounting fixture not included with standard shipment. See document 67188.
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 26plus; 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.
17695 SBE 4 to SBE 26/26plus/53 interface cable, RMG-3FS to RMG-3FS, 0.3 m (DN 30566) 17695 included if 26plus is ordered with SBE 4M (26p-3c); this is spare.

171752 included if 26plus is ordered with SBE 4M (26p-3c) & wet-pluggable connectors (26p-4b); 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)
50286 SBE 4 mounting bracket for SBE 26/26plus/53 Mount bracket included if 26plus is ordered with SBE 4M (26p-3c); this is spare.
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.

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.

  • SBE 4Ms shipped with optional Anti-Foulant Devices for moored applications before 2002 used a smaller anti-foulant device inside Tygon tubing that attached to end of conductivity cell, & did not include 50315. For those SBE 4Ms, order 50315 & 801542 AF24173 Anti-Foulant Devices first time you need new Anti-Foulant Devices. Once you have 50315, order 801542 AF24173 Anti-Foulant Devices as needed.
  • SBE 4Ms shipped with optional Anti-Foulant Devices for moored applications after 2002 include 50315 installed on SBE 4M. Order 801542 AF24173 Anti-Foulant Devices as needed.

 
50315 fitting & anti-foulant device

801542 AF24173 Anti-Foulant Device pair (spare, bagged, labeled for shipping)
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.

 

Cables

  • 801225 To computer COM port (from 4-pin RS-232 XSG connector), 2.4 m, DN 32421
  • 801374 To computer COM port (from 4-pin RS-232 Wet-pluggable connector), 2.4 m, DN 32715
  • 801584 To computer COM port (from 6-pin RS-422/RS-485 AG connector), 2.4 m, DN 33051
  • 802124 To computer COM port (from 6-pin RS-422/RS-485 Wet-pluggable connector), 2.4 m, DN 33661
  • 17695 To SBE 4 (RMG connectors),0.28 m, DN 30566
  • 171752 To SBE 4 (Wet-pluggable connectors), 0.28 m, DN 32671

Mount Kits

  • 50102 SBE 26 Mounting Fixture (document 67188)

Spare Parts

  • 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)
  • 50092 Jackscrew kit for SBE 16, 17plus, 19, 21, 25, 26/26plus, 52-MP, 53, 54, AFM, or PDIM
  • 50056 Hardware kit for SBE 26/26plus, 53, or 54 (document 67016)
  • 801575 Battery Cover Spacer / Adapter, 12 D alkaline cells to 6 DD Electrochem Lithium cells
  • 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)

Compare  Moored / Time Series Recording Instruments

SBE Measures
(C, T, P)
Auxiliary Sensors Memory Power Communication Real-Time
Data
Comments
Internal External
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 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; 
1 RS-232
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 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
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
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

SBE 37-SIP-IDO MicroCAT C-T-DO (P) Sensor

C, T, P* Integrated DO 8 Mb   RS-232 or -485 Integral pump
Water Quality Monitor (WQM) C, T, P Integrated DO, chlorophyll fluorescence, turbidity (WQMx adds CDOM fluorescence, replaces turbidity with backscattering)   RS-232 Jointly developed by Sea-Bird Electronics and WET Labs; manufactured by WET Labs
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 39-IM Temperature (P) Recorder T, P*   32 Mb   Inductive modem  
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
* = optional
products are no longer in production. Follow the links above to the product page to retrieve manuals and application notes for these older products.