The SBE 25plus Sealogger is the ideal research-quality CTD profiler for coastal, estuarine, and deep-water deployments. The battery-powered 25plus samples at 16 Hz and records data in memory, eliminating the need for a large vessel, electro-mechanical sea cable, and on-board computer, and can also transmit data in real-time. Pump-controlled, T-C ducted flow minimizes salinity spiking caused by ship heave and allows for slow descent rates without slowing sensor responses, improving dynamic accuracy and resolving small scale structure in the water column. The 25plus supports numerous auxiliary sensors with eight A/D channels and two RS-232 data channels, with enough power for power-hungry sensors such as nitrate (e.g., Satlantic SUNA) and CO2. The alkaline battery pack provides power for up to 55 hours of profiling. The unique end cap design provides easy access to bulkhead connectors, simplifying the addition and removal of sensors.
The 25plus is frequently used autonomously, recording data internally. It can also provide real-time acquisition and display over short cables via the RS-232 interface; a load-bearing cable for hand-hauled, real-time profiling is available. External power and communication over 10,000 m of single-core, armored cable can be provided with the SBE 36 Deck Unit and PDIM. The 25plus is easily integrated with a Sea-Bird Water Sampler; both real-time and autonomous auto-fire operations are possible.
- SBE 3F Temperature sensor, SBE 4C Conductivity sensor, strain-gauge Pressure sensor.
- Channels for up to ten auxiliary sensors (eight voltage output sensors and two RS-232 serial output sensors).
- RS-232 interface, internal memory, and internal alkaline battery pack (can be powered externally).
- Pump-controlled, T-C ducted flow to minimize salinity spiking.
- Upload via external bulkhead connector or fast upload of large data sets via internal USB connector.
- Depths to 600 or 6800 m.
- Stainless steel protection cage.
- Seasoft© V2 Windows software package (setup, data upload, real-time data acquisition, and data processing).
- Newest version of our Sealogger, field-proven since 1989.
- Five-year limited warranty.
- Unique internal-field conductivity cell permits use of T-C Duct, minimizing salinity spiking.
- Aged and pressure-protected thermistor has a long history of exceptional accuracy and stability.
- Strain-gauge pressure sensor with temperature compensation is available in eight ranges (to 7000 m).
- Pump runs continuously, providing correlation of CTD and plumbed auxiliary sensor measurements.
- Plastic (600 m) or aluminum (6800 m) housing.
- XSG/AG or wet-pluggable MCBH connectors.
- SBE 5P (600 m) or SBE 5T (10,500 m) pump.
- Sea-Bird Scientific auxiliary sensors — dissolved oxygen (SBE 63 Optical DO Sensor or SBE 43 [membrane-type] DO Sensor), pH (SBE 18 or 27), fluorescence, oil, radiance (PAR), light transmission, turbidity, nitrates, etc.
- Auxiliary sensors from other manufacturers — altimeter, CO2, etc.
- Load-bearing underwater cables for hand-hauled, real-time profiling .
- SBE 36 CTD Deck Unit & PDIM or SBE 33 Deck Unit & Sea-Bird water sampler (real-time operation on single-core armored cable to 10,000 m).
- Plastic shipping case.
|Conductivity||0 to 7 S/m|
|Temperature||-5 to +35 °C|
|Pressure||0 to 20 / 100 / 350 / 600 / 1000 / 2000/ 3500 / 7000 m|
|Conductivity||± 0.0003 S/m|
|Temperature||± 0.001 °C|
|Pressure||± 0.1% of full scale range|
|Pressure||0.002% of full scale range|
|Memory & Data Storage||2 GByte non-volatile FLASH.
(approximately 1320 hours of data from T, C, P, & 8 auxiliary voltage sensors; auxiliary serial sensor data is sensor dependent)
|Power Supply & Consumption||12 alkaline D-cell battery pack, 55 hours CTD profiling (see manual)|
|Optional External Power||14 - 20 VDC; consult factory for required current|
|Auxiliary Sensors||Power out up to 1.2 A across all channels at 12 VDC (1 A maximum per channel);
Voltage sensor A/D resolution 16 bits and input range 0-5 VDC
|Housing, Depth Rating, & Weight (with pump & cage)||Acetal Copolymer Plastic, 600 m, in air 20.0 kg, in water (approximately) 11.5 kg
7075 Aluminum, 6800 m, in air 22.5 kg, in water (approximately) 13.5 kg.
|Cage||In air 6.7 kg, in water (approximately) 5.9 kg|
Which Sea-Bird profiling CTD is best for my application?
Sea-Bird makes four main profiling CTD instruments, as well as several profiling CTD instruments for specialized applications.
In order of decreasing cost, the four main profiling CTD instruments are the SBE 911plus CTD, SBE 25plus Sealogger CTD, SBE 19plus SeaCAT Profiler CTD, and SBE 49 FastCAT CTD Sensor:
- The SBE 911plus is the world’s most accurate CTD. Used by most leading oceanographic institutions, the SBE 911plus is recognized for superior performance, reliability, and ease-of-use. Features include: modular conductivity and temperature sensors, Digiquartz pressure sensor, TC-Ducted Flow and pump-controlled time response, 24 Hz sampling, 8 A/D channels and power for auxiliary sensors, modem channel for real-time water sampler control without data interruption, and optional 9600 baud serial data uplink. The SBE 911plus system consists of: SBE 9plus Underwater Unit and SBE 11plus Deck Unit. The SBE 9plus can be used in self-contained mode when integrated with the optional SBE 17plus V2 Searam. The Searam provides battery power, internal 24 Hz data logging, and an auto-fire interface to an SBE 32 Carousel Water Sampler to trigger bottle closures at pre-programmed depths.
- The SBE 25plus Sealogger is the choice for research work from smaller vessel not equipped for real-time operation, or use by multi-discipline scientific groups requiring configuration flexibility and good accuracy and resolution on a smaller budget. The SBE 25plus is a battery-powered, internally-recording CTD featuring the same modular C & T sensors used on the SBE 9plus CTD, an integral strain gauge pressure sensor, 16 Hz sampling, 2 GB of memory, TC-Ducted Flow and pump-controlled time response, and 8 A/D channels plus 2 RS-232 channels and power for auxiliary sensors. Real-time data can be transmitted via RS-232 simultaneous with data recording. The SBE 25plus integrates easily with an SBE 32 Carousel Water Sampler or SBE 55 ECO Water Sampler for real-time or autonomous operation.
- The SBE 19plus V2 SeaCAT Profiler is known throughout the world for good performance, reliability, and ease-of-use. An economical, battery-powered, internally-recording mini-CTD, the SBE 19plus V2 is a good choice for basic hydrography, fisheries research, environmental monitoring, and sound velocity profiling. Features include 4 Hz sampling, 6 differential A/D channels plus 1 RS-232 channel and power for auxiliary sensors, 64 MB of memory, and pump-controlled conductivity time response. Real-time data can be transmitted via RS-232 simultaneous with data recording, The SBE 19plus V2 integrates easily with an SBE 32 Carousel Water Sampler or SBE 55 ECO Water Sampler for real-time or autonomous operation.
- The SBE 49 FastCAT is an integrated CTD sensor intended for towed vehicle, ROV, AUV, or other autonomous profiling applications. Real-time data ‑ in raw format or in engineering units ‑ is logged or telemetered by the vehicle to which it is mounted. The SBE 49’s pump-controlled, TC-ducted flow minimizes salinity spiking, and its 16 Hz sampling provides very high spatial resolution of oceanographic structures and gradients. The SBE 49 has no memory or internal batteries. The SBE 49 integrates easily with an SBE 32 Carousel Water Sampler or SBE 55 ECO Water Sampler for real-time operation.
The specialized profiling CTD instruments are the SBE 52-MP Moored Profiler, Glider Payload CTD, and SBE 41/41CP Argo CTD module:
- The SBE 52-MP Moored Profiler is a conductivity, temperature, pressure sensor, designed for moored profiling applications in which the instrument makes vertical profile measurements from a device that travels vertically beneath a buoy, or from a buoyant sub-surface sensor package that is winched up and down from a bottom-mounted platform. The 52-MP's pump-controlled, TC-ducted flow minimizes salinity spiking. The 52-MP can optionally be configured with an SBE 43F dissolved oxygen sensor.
- The Glider Payload CTD measures conductivity, temperature, and pressure, and optionally, dissolved oxygen (with the modular SBE 43F DO sensor). It is a modular, low-power profiling instrument for autonomous gliders with the high accuracy necessary for research, inter-comparison with moored observatory sensors, updating circulation models, and leveraging data collection opportunities from operational vehicle missions. The pressure-proof module allows glider users to exchange CTDs (and DO sensors) in the field without opening the glider pressure hull.
- Argo floats are neutrally buoyant at depth, where they are carried by currents until periodically increasing their displacement and slowing rising to the surface. The SBE 41/41CP CTD Module obtains the latest CTD profile each time the Argo float surfaces. At the surface, the float transmits in-situ measurements and drift track data to the ARGOS satellite system. The SBE 41/41CP can be integrated with Sea-Bird's Navis float or floats from other manufacturers. The SBE 41N CTD is integrated with Sea-Bird's Navis Float with Integrated Biogeochemical Sensors and Navis BGCi + pH Float with Integrated Biogeochemical Sensors.
See Product Selection Guide for a table summarizing the features of our profiling CTDs.
What are the recommended practices for inspecting, cleaning, and replacing o-rings?
Inspecting and Cleaning O-Rings and Mating Surfaces:
- Remove any water from the o-rings and mating surfaces with a lint-free cloth or tissue.
- 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.
- 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.
- 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.
- 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.
- 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).
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
What are the recommended practices for storing sensors at low temperatures, and deploying at low temperatures or in frazil or pancake ice?
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.
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.
In general, neither the accuracy of the temperature measurement nor the survival of the temperature sensor will be affected by ice.
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.
I am ordering a CTD and want to use auxiliary sensors. Should I order them from Sea-Bird also, or deal directly with the sensors’ manufacturers?
This depends on your own expertise and resources. We have extensive experience in integrating and supporting a wide range of auxiliary sensors, but not everything under the sun. We have a large list of commonly used sensors that we routinely offer for sale (see Third Party Sensor Configuration).
When you purchase any of these auxiliary sensors from Sea-Bird, we are able to apply this experience to integrating the sensors with the CTD. The integration includes installing the sensors (with appropriate mounting kits and cables) in a manner that puts each sensor in the best possible orientation for optimum performance. It also includes configuring the CTD system and software to accept the sensors’ inputs and properly display the data, and testing the entire system, typically in a chilled saltwater bath overnight, to confirm proper operation. Having done the integration, we also support the entire system in terms of follow-on service and end-user support with operational and data analysis questions *. There is significant added value in our integration service, and there is some extra cost for this, compared to doing it yourself. However, we do not base our business on selling services, and the prices charged for Third Party sensors carry minimal mark-ups that vary depending on the pricing we are offered by the manufacturers. In some cases we can sell at the manufacturer's list price, and in others we have to add margin.
1. As described in our Warranty, auxiliary sensors manufactured by other companies are warranted only to the limit of the warranties provided by their original manufacturers (typically 1 year).
2. Click here for information on repairing / recalibrating auxiliary sensors manufactured by other companies.
Is it necessary to put my instrument in water to test it? Will I destroy the conductivity cell if I test it in air?
It is not necessary to put the instrument in water to test it. It will not hurt the conductivity cell to be in air.
If there is a pump on the instrument, it should not be run for extended periods in air.
- Profiling instruments (SBE 9plus, 19, 19plus, 19plus V2, 25, 25plus, 49) and some moored instruments (all pumped MicroCATs with integral dissolved oxygen (DO), and pumped MicroCATs without DO with firmware 3.0 and later) do not turn on the pump unless the conductivity frequency is above a specified minimum value (minimum value is hard-wired in 9plus, user-programmable in other instruments). This prevents the pump from turning on in air. See the instrument manual for details.
- If your instrument does not check for conductivity frequency before turning on the pump:
- For moored SeaCATs (16, 16plus, 16plus-IM, 16plus V2, 16plus-IM V2): Disconnect the pump cable for the test.
- For older pumped MicroCATs: orient the MicroCAT to provide an upright U-shape for the plumbing. Then fill the inside of the pump head with water via the pump exhaust tubing; this will provide enough lubrication to prevent pump damage during brief testing.
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.
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.
I want to add an auxiliary sensor to my CTD (SBE 9plus, 16, 16plus, 16plus-IM, 16plus V2, 16plus-IM V2, 19, 19plus, 19plus V2, 21, 25, or 25plus). Assuming the auxiliary sensor is compatible with the instrument, what is the procedure?
Adding the sensor(s) is reasonably straightforward:
- Mount the sensor; a poor mounting scheme can result in poor data.
Note: If the new sensor will be part of a pumped system, the existing plumbing must be modified; consult Sea-Bird for details.
- Attach the new cable.
- (not applicable to 9plus used with 11plus Deck Unit) Using the appropriate terminal program — Enable the channel(s) in the CTD, using the appropriate instrument command.
- Using Seasave V7 or SBE Data Processing — Modify the CTD configuration (.con or .xmlcon) file to reflect the new sensor, and type in the calibration coefficients.
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 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 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.
I want to change the pressure sensor on my CTD, swapping it as needed to get the best data for a given deployment depth. Can I do this myself, or do I need to send the instrument to Sea-Bird?
On most of our instruments, replacement of the pressure sensor should be performed at Sea-Bird. We cannot extend warranty coverage if you replace the pressure sensor yourself.
However, we recognize that you might decide to go ahead and do it yourself because of scheduling/cost issues. Some guidelines follow:
- Perform the swap and carefully store the loose sensor on shore in a laboratory or electronics shop environment, not on a ship. The pressure sensor is fairly sensitive to shock, and a loose sensor needs to be stored carefully. Dropping the sensor will break it.
- Some soldering and unsoldering is required. Verify that the pressure sensor is mounted properly in your instrument. Properly re-grease and install the o-rings, or the instrument will flood.
- Once the sensor is installed, back-fill it with oil. Sea-Bird uses a vacuum-back filling apparatus that makes this job fairly easy. We can provide a drawing showing the general design of the apparatus, which can be modified and constructed by your engineers.
- For the most demanding work, calibrate the sensor on a deadweight tester to ensure proper operation and calibration.
- Enter the calibration coefficients for the new sensor in:
- the CTD configuration (.con or .xmlcon) file, using Seasave V7 or SBE Data Processing, and
- (for an instrument with internally stored calibration coefficients) the CTD EEPROM, using the appropriate terminal program and the appropriate calibration coefficient commands
Note: This discussion does not apply to the SBE 25 (not 25plus), which uses a modular pressure sensor (SBE 29) mounted externally on the CTD. Swap the SBE 29 as desired, use the CC command in Seaterm or SeatermAF to enter the new pressure range and pressure temperature compensation value, and type the calibration coefficients for the new sensor into the CTD configuration (.con or .xmlcon) file in Seasave V7 or SBE Data Processing.
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.
Can I brush-clean and replatinize the conductivity cell myself? How often should this be done?
Brush-cleaning and replatinizing should be performed at Sea-Bird. We cannot extend warranty coverage if you perform this work yourself.
The brush-cleaning and replatinizing process requires specialized equipment and chemicals, and the disassembly of the sensor. If performed incorrectly, you can damage the cell. Additionally, the sensor must be re-calibrated when the work is complete.
Sea-Bird determines whether brush-cleaning and replatinizing is required based upon how far the calibration has drifted from the original calibration. Typically, a conductivity sensor on a profiling CTD requires brush-cleaning and replatinizing every 5 years.
What is the function of the zinc anode on some instruments?
A zinc anode attracts corrosion and prevents aluminum from corroding until all the zinc is eaten up. Sea-Bird uses zinc anodes on an instrument if it has an aluminum housing and/or end cap. Instruments with titanium or plastic housings and end caps (for example, SBE 37 MicroCAT) do not require an anode.
Check the anode(s) periodically to verify that it is securely fastened and has not been eaten away.
I sent my conductivity sensor to Sea-Bird for calibration, and you also performed a Cleaning and Replatinizing (C &P). You sent the instrument back with 2 sets of calibration data. What does this mean?
The post-cruise calibration contains important information for drift calculations. The post-cruise calibration is performed on the cell as we received it from you, and is an indicator of how much the sensor has drifted in the field. Information from the post-cruise calibration can be used to adjust your data, based on the sensor’s drift over time. See Application Note 31: Computing Temperature and Conductivity Slope and Offset Correction Coefficients from Laboratory Calibrations and Salinity Bottle Samples.
If the sensor has drifted significantly (based on the data from the post-cruise calibration), Sea-Bird performs a C & P to restore the cell to a state similar to the original calibration. After the C & P, the sensor is calibrated again. This calibration serves as the starting point for future data, and for the sensor’s next drift calculation.
The C & P tends to return the cell to its original state. However, there are many subtle factors that may result in the post-C & P calibration not exactly matching the original calibration. Basically, the old platinizing is stripped off and new platinizing is plated on. Anything in this process that alters the cell slightly will result in a difference from the original calibration. We compare the calibration after C & P with the original calibration, not to make any drift analysis, but to make sure we did not drastically alter the cell, or that the cell was not damaged during the C & P process.
How accurate is salinity measured by my CTD? What factors impact accuracy?
One of the reasons that this is not a simple question is that there are several factors to take into consideration regarding the error margin for practical salinity measurements. Salinity itself is a derived measurement from temperature, conductivity, and pressure, so any errors in these sensors can propagate to salinity. For example, our initial accuracy specification for the SBE 3plus temperature sensor and SBE 4 conductivity sensor on an SBE 9plus CTD is approximately equivalent to an initial salinity accuracy of 0.003 PSU (note that conductivity units of mS/cm are roughly equivalent in terms of magnitude to PSU).
However, another issue to consider is that this accuracy is defined for a clean, well-mixed calibration bath. In the ocean, some of the biggest factors that impact salinity accuracy are 1) sensor drift from biofouling or surface oils for conductivity in particular and 2) dynamic errors that can occur on moving platforms, particularly when conditions are rapidly changing, which will be true for all sensors that measure salinity. Sea-Bird provides recommendations, design features such as a pumped flow path, and data processing routines to align and improve data for the salinity calculation to account for thermal transients and hysteresis, and to match sensor response times. Depending on the environment and the steepness of the gradient, and after careful data processing, this may continue to have an impact on salinity on the order of 0.002 PSU or more, for example. For more details, see Application Note 82.
Lastly, note that salinity in PSU is calculated according to the Practical Salinity Scale (PSS-78), which is defined as valid for salinity ranges from 2 – 42 PSU.
How can I tell if the conductivity cell on my CTD is broken?
Conductivity cells are made of glass, which is breakable.
- If a cell is cracked, it typically causes a salinity shift or erratic data.
- However, if the crack occurs at the end of the cell, the sensor will continue to function normally until water penetrates the epoxy jacket. Post-cruise calibration results will reveal whether or not water has penetrated the epoxy jacket.
Inspect the cell thoroughly and make sure that it isn’t cracked or abused in any way.
- (SBE 9plus, 25, or 25plus) If the readings are good at the surface but erratic at depth, it is likely that the problem is in the cable or the connector, not the conductivity cell. Check the connections, making sure that you burp the connectors when you plug them in (see Application Note 57: Connector Care and Cable Installation). Check the cable itself (swap with a spare cable, if available).
- If the readings are incorrect at the surface but good after a few meters, it is likely that the problem is flow-related. Verify that the pump is working properly. Check the air bleed valve (the white plastic piece in the Y-fitting, which is installed on vertically deployed CTDs) to see if it is clogged; clean out the small hole with a piece of fine wire supplied with your CTD.
- If the readings are incorrect for the entire cast, there may be an incorrect calibration coefficient or the cell may be cracked.
- Check the conductivity calibration coefficients in the configuration (.con or .xmlcon) file.
- Do a frequency check on the conductivity cell. Disconnect the plumbing on the cell. Rinse the cell with distilled or de-ionized water and blow it dry (use your mouth and not compressed air, as there tends to be oil in the air lines on ships). With the cell completely dry, check the frequency reading. It should read within a few tenths of a Hz of the 0 reading on your Calibration Sheet. If it does not, something is wrong with the cell and it needs to be repaired.
Should I purchase spare sensors for my SBE 9plus or 25plus?
Most customers purchase spare conductivity and temperature sensors. These sensors are exposed to ocean conditions and therefore more likely to be broken than an internal sensor. It is also very easy to change them because they are independent sensors that plug into the CTD main housing.
Most customers do not purchase spare pressure sensors for the following reasons:
- The pressure sensor is inside the CTD main housing. It is very well protected against damage of any kind, and reliability of this sensor is extremely good.
- The sensor is expensive.
- It is difficult to change the sensor in the field.
What do I need to send to Sea-Bird for calibration of my SBE 9plus, 25, or 25plus?
For calibration of the temperature and conductivity sensors, only the sensor modules need to be sent to Sea-Bird. It is not necessary to send the CTD main housing. See Shipping SBE 9plus, 25, and 25plus Temperature and Conductivity Sensors for details.
It is usually not necessary to recalibrate the pressure sensor as frequently as the temperature and conductivity sensors. Experience has shown that the sensor’s sensitivity function almost never changes; only the offset drifts. The offset drift can easily be measured by reading deck pressure against a barometer. This small drift is easily corrected (Seasave V7 and SBE Data Processing provide an entry for the offset drift in the instrument .con or .xmlcon file).
- SBE 9plus and 25plus — If the pressure sensor does need to be calibrated, the entire CTD must be shipped to Sea-Bird.
- SBE 25 — If the pressure sensor does need to be calibrated, only the modular SBE 29 pressure sensor needs to be sent to Sea-Bird. It is not necessary to send the CTD main housing.
What are the major steps involved in taking a cast with a Profiling CTD?
Following is a brief outline of the major steps involved in taking a CTD cast, based on generally accepted practices. However, each ship, crew, and resident technicians have their own operating procedures. Each scientific group has their own goals. Therefore, observe local ship and scientific procedures, particularly in areas of safety. Before the cruise a discussion of the planned work is advisable between the ship’s crew, resident technicians, and scientific party. At this time discuss and clarify any specific ship’s procedures.
Note: The following procedure was written for an SBE 9plus CTD operating with an SBE 11plus Deck Unit. Modify the procedure as necessary for your CTD.
10 to 15 minutes before Station:
- Review the next cast’s plan, including proposed maximum cast depth, bottom depth, and number of bottles to close and depths. If the cast will be close to the bottom, familiarize yourself with the bottom topography.
- Verify that all water samples have been obtained from the bottles from the previous cast. If so, drain the bottles and cock them. Hand manipulate each Carousel latch as you cock the bottle to ensure it is free to release and is not stuck in some way.
- Remove the soaker tubes from the conductivity cells.
- Remove any other sensor covers.
- With permission from the deck crew, power up the CTD. Check the Deck Unit front panel display to verify communication. Perform a quick frequency check of the main sensors.
- Start Seasave. Set up a fixed display. Select Do not archive data for this cast. Start acquisition and view the data to verify the system is operational.
- Clean optical sensor windows, and perform any required air calibration.
- Stop acquisition. Do Not turn the CTD Deck Unit off. Select begin archiving data immediately. Set up the plot scales and status line.
5 minutes before Station:
- Start the ship's depth sounder and obtain a good depth reading. Be careful reading the depth sounder; if it is improperly configured the trace will wrap around the plot and be incorrect. The bottom depth should be close to the expected charted depth.
- Fill out any parts of the cast log that can be done at this time.
On Station, On Deck:
- Verify the position and the bottom depth.
- The computer operator should begin filling out the software header.
- After receiving word from the bridge that they are on station and ready to begin, untie the CTD and move it into position. If this requires hydraulics, ensure you have the appropriate people in place and permission.
- Position the CTD under the block. Have the winchman remove any slack from the wire.
- Notify the computer room that the CTD is ready for launch. The computer room should start acquiring data.
- Obtain a barometric pressure reading and note it on the cast sheet.
- When the bridge, computer room, and winchman are ready (and you have permission to proceed), put the CTD in the water.
- Have the winchman lower the CTD to 10 meters (his readout), hold for 1 minute, and then bring it back to the surface. One operator should remain on deck to help the winchman see when to stop the CTD. The CTD should be far enough below the surface so that the package does not break the surface in the swells.
CTD Soaking at the Surface:
- Finish filling out the cast log. Re-check the bottom depth.
- Fill out the computer software log.
- Hold the CTD at the surface for at least 3 minutes.
- Check the status line to verify that the CTD values are correct. The pressure should be the soaking depth of the CTD. Comparing the CTD temperature and salinity to the ship's thermosalinograph is helpful. Log the information (CTD and thermosalinograph) on the cast sheet.
Starting the Cast:
- Call the winchman and have him start the cast down. Typical lowering speed is 1 m/sec, modified for conditions as needed.
- Watch the computer output and verify that the system is working.
During the Cast:
- Closely monitor the CTD output for malfunctions. Sudden noise in a channel is often a sign of a leaking cable. A periodically flashing error light on the Deck Unit is a sign of a bad spot in the slip rings. The modulo error count (usually on the status line) provides an indication of telemetry integrity; on a properly functioning system, there will be no modulo errors.
- Note any odd behavior or problems on the cast sheet. Keeping good notes and records is of critical importance. While you may remember what happened an hour from now, in the months that follow, these notes will be a vital link to the cruise as you process the data.
- Monitor the bottom depth. This is especially critical if the cast will be close to the bottom, or you are working in an area with varying topography such as in a canyon. Running the CTD into the bottom can cause serious (and expensive) damage.
Approaching the Bottom:
- Take extra care if the cast will take the CTD close to the bottom. Monitor the bottom depth, pinger, and altimeter, if available. As you get within 30 meters of the bottom, slow down the cast to 0.5 m/sec. If you wish to get closer than 10 m above the bottom, slow down to 0.2 m/sec. Keep in mind that ship roll will cause the CTD depth to oscillate by several meters.
- If the CTD does touch bottom, it will be apparent from the sudden, low salinity spike. A transmissometer, if installed, will also show a sudden low spike.
- Adjust these numbers and procedures as conditions dictate to avoid crashing the CTD into the bottom.
- When the CTD reaches the maximum cast depth, call the winchman and stop the descent.
- Log a position on the cast sheet. If a bottle will be closed at the bottom, allow the CTD to soak for at least 1 minute (preferably several minutes) and then close the bottle. Verify that the software records the bottle closure confirmation.
- Start the CTD upcast. Stop the CTD ascent at any other bottle closure depths. For each bottle, soak for at least 1 minute (preferably several minutes) and then close the bottle.
End of the Cast:
- As the CTD approaches the surface, have someone help spot for the winchman. Stop the CTD below the surface. Close a bottle if desired.
- When ready, recover the CTD. Avoid banging the system against the ship.
CTD Back on Board:
- Stop data acquisition and power off the CTD.
- Move the CTD it into its holding area and secure it.
- See Application Note 2D: Instructions for Care and Cleaning of Conductivity Cells for details on rinsing, cleaning, and storing the conductivity cell. Fill the conductivity cell with clean DI (or 1% Triton-X) and secure the filler device to the CTD frame. Freezing water in a conductivity cell will break the cell.
- See Application Note 64: SBE 43 Dissolved Oxygen Sensor - Background Information, Deployment Recommendations, and Cleaning and Storage for details on rinsing, cleaning, and storing SBE 43 (membrane-type) dissolved oxygen sensors; see the SBE 63 manual for details on rinsing, cleaning, and storing SBE 63 optical dissolved oxygen sensors.
- Rinse any optical sensors.
- Rinse the water sampler latches with clean water.
- Draw water samples from the bottles.
After the Cast:
- Re-plot the data and look at any channels that were not displayed in real time.
- Perform diagnostics and take a first pass through processing.
- Verify that the data is good (at least on a first-order basis) at this point, when you can still re-do the cast. Many casts are lost because they are not analyzed until months later, when the problems are discovered.
- Final processing may need to wait until bottle salts and post-cruise lab calibrations are available.
Should I collect water samples (close bottles) on the downcast or the upcast?
Most of our CTD manuals refer to using downcast CTD data to characterize the profile. For typical configurations, downcast CTD data is preferable, because the CTD is oriented so that the intake is seeing new water before the rest of the package causes any mixing or has an effect on water temperature.
However, if you take water samples on the downcast, the pressure on an already closed bottle increases as you continue through the downcast; if there is a small leak, outside water is forced into the bottle, contaminating the sample with deeper water. Conversely, if you take water samples on the upcast, the pressure decreases on an already closed bottle as you bring the package up; any leaking results in water exiting the bottle, leaving the integrity of the sample intact. Therefore, standard practice is to monitor real-time downcast data to determine where to take water samples (locations with well-mixed water and/or with peaks in the parameters of interest), and then take water samples on upcast.
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.
Can I deploy my profiling CTD for monitoring an oil spill?
Sea-Bird CTDs can be deployed in oil; the oil will not cause long-term damage to the CTD. If the oil coats the inside of the conductivity cell and coats the dissolved oxygen sensor membrane, it can possibly affect the sensor’s calibration (and thus affect the measurement and the data). Simple measures can reduce the impact, as follows:
- To minimize the ingestion of oil into the conductivity cell and onto the DO sensor membrane:
SBE 19, 19plus, 19plus V2, 25, or 25plus CTD:
Set up the CTD so that the pump does not turn on until the CTD is in the water and below the layer of surface oil, minimizing ingestion of oil (however, some oil will still enter the system). Pump turn-on is controlled by two user-programmable parameters: the minimum conductivity frequency and the pump delay.
Set the minimum conductivity frequency for pump turn-on above the instrument’s zero conductivity raw frequency (shown on the conductivity sensor Calibration Sheet), to prevent the pump from turning on when the CTD is in air. Note that this is the same as our typical recommendation for setting the minimum conductivity frequency.
For salt water and estuarine applications - typical value = zero conductivity raw frequency + 500 Hz
For fresh/nearly fresh water - typical value = zero conductivity raw frequency + 5 Hz
If the minimum conductivity frequency is too close to the zero conductivity raw frequency, the pump may turn on when the CTD is in air as result of small drifts in the electronics. Another option is to rely only on the pump turn-on delay time to control the pump; if so, set a minimum conductivity frequency lower than the zero conductivity raw frequency.
Set the pump turn-on delay time to allow enough time for you to lower the CTD below the surface oil layer after the CTD is in the water (the CTD starts counting the pump delay time after the minimum conductivity frequency is exceeded). You may need to set the pump delay time to be longer than our typical 30-60 second recommendation.
The current minimum conductivity frequency and pump delay can be checked by sending the status command to the CTD (DS or GetCD, as applicable). Commands for modifying these parameters are:
- SBE 19: SP (SBE 19 responds with prompts for setting up these parameters)
- SBE 19plus and 19plus V2: MinCondFreq=x and PumpDelay=x (where x is the value you are programming).
- SBE 25: CC (SBE 25 responds with a series of setup prompts, including setting up these parameters)
- SBE 25plus: SetMinCondFreq=x and SetPumpDelay=x (where x is the value you are programming).
SBE 9plus CTD:
Minimum conductivity frequency and pump delay are not user-programmable for the 9plus.
If you are using your 9plus with the 11plus Deck Unit, the Deck Unit provides power to the 9plus. Without power, the pump will not turn on. At the start of the deployment, to ensure that you have cleared the surface oil layer before the pump turns on, do not turn on the Deck Unit until the 9plus is below the surface oil layer. Similarly, on the upcast, turn off the Deck Unit before the 9plus reaches the surface oil layer.
If your 9plus is equipped with the optional manual pump control, you can enable manual pump control via the Pump Control tab in Seasave V7’s Configure Inputs dialog box. Once enabled, you can turn the pump on and off from Seasave V7’s Real-Time Control menu. Do not turn the pump on until the CTD is below the surface oil layer. On the upcast, turn the pump off before the CTD reaches the surface oil layer.
- To reduce the effect of the ingestion of oil into the conductivity cell and onto the DO sensor membrane or optical window:
After each recovery, rigorously follow the cleaning and storage procedures in the following application notes ‑
- Application Note 2D: Instructions for Care and Cleaning of Conductivity Cells
- Application Note 64: SBE 43 Dissolved Oxygen Sensor – Background Information, Deployment Recommendations, and Cleaning and Storage
- SBE 63 Optical Dissolved Oxygen Sensor manual
Quick Reference Sheets for Oil Spill Deployment:
What are the typical data processing steps recommended for each instrument?
Section 3: Typical Data Processing Sequences in the SBE Data Processing manual provides typical data processing sequences for our profiling CTDs, moored CTDs, and thermosalinographs. Typical values for aligning, filtering, etc. are provided in the sections detailing each module of the software. This information is also documented in the software's Help file. To download the software and/or manual, go to SBE Data Processing.
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.
|25||P||.||1 – 600 m (plastic)||1 – 20 m strain gauge||1 – XSG/AG||0 - standard cage (vertical)|
|2 – 6800 m (aluminum)||2 – 100 m strain gauge||2 – MCBH||1 - SBE 32 extension stand (horizontal)|
|3 – 350 m strain gauge||2 - SBE 32C/32SC (vertical)|
|4 – 600 m strain gauge||3 - SBE 55 (vertical)|
|5 – 1000 m strain gauge||4 - no cage|
|6 – 2000 m strain gauge|
|7 – 3500 m strain gauge|
|8 – 7000 m strain gauge|
Example: 25P.2820 is an SBE 25plus with 6800 m housing, 7000 m strain gauge pressure sensor, MCBH connectors, and standard cage. See table below for description of each selection:
Sealoggerplus CTD - 16 Hz sampling rate. With modular temperature (SBE 3F) & conductivity (SBE 4C) sensors & TC Duct, submersible pump (SBE 5), internal strain gauge pressure sensor, 2 GB memory, eight A/D input channels (0 - 5 volt input range), two RS-232 input channels. Includes data I/O and pump Y-cable, 20 meter data I/O cable, protective cage, Seasoft software, & complete documentation.
SBE 25plus, a profiling CTD, is powered by internal batteries & records data in memory.
In addition, 25plus can be deployed:
|SBE 25plus Housing (depth) Selections — MUST SELECT ONE|
|25P.1xxx||600 m plastic housing for CTD and SBE 5P plastic pump||
Housing material & depth rating does not apply to sensors — SBE 3F temperature sensor & 4C conductivity sensor are aluminum, regardless of 25plus housing option, & are rated for 6800 m.
|25P.2xxx||6800 m aluminum housing for CTD and SBE 5T titanium pump|
|SBE 25plus Pressure Sensor Selections — MUST SELECT ONE|
|25P.x1xx||20 m strain gauge pressure sensor||Pressure sensor is installed in connector end cap, & is not field replaceable / swappable. While highest pressure rating gives you most flexibility in using 25plus, 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 pressure sensor's full scale range. For example, comparing 2000 & 7000 m sensors:
|25P.x2xx||100 m strain gauge pressure sensor|
|25P.x3xx||350 m strain gauge pressure sensor|
|25P.x4xx||600 m strain gauge pressure sensor|
|25P.x5xx||1000 m strain gauge pressure sensor|
|25P.x6xx||2000 m strain gauge pressure sensor|
|25P.x7xx||3500 m strain gauge pressure sensor|
|25P.x8xx||7000 m strain gauge pressure sensor|
|SBE 25plus Connector Selections — MUST SELECT ONE|
|25P.xx1x||XSG/AG connectors on C & T sensors, pump, related cables, and 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.
|25P.xx2x||Wet-pluggable (MCBH) connectors on C & T sensors, pump, related cables, and data I/O cable|
|SBE 25plus Integration Selections — MUST SELECT ONE|
|25P.xxx0||Standard cage (vertical plumbing)||Includes cage, mounting of 25plus to cage, and plumbing installed for vertical deployment.|
|25P.xxx1||SBE 32 Carousel Water Sampler extension stand (horizontal plumbing)||Includes cage, mounting of 25plus to cage, and plumbing installed for horizontal deployment in SBE 32 extension stand. Does not include extension stand or hardware to mount 25plus cage to extension stand.|
|25P.xxx2||SBE 32C/32SC Carousel Water Sampler (vertical plumbing)||No cage. Includes mounts for vertical mounting to SBE 32C Compact or 32SC Sub-Compact Carousel Water Sampler, and plumbing installed for vertical deployment.|
|25P.xxx3||SBE 55 ECO Water Sampler (vertical plumbing)||No cage. Includes mounts for vertical mounting to SBE 55 ECO Water Sampler, and plumbing installed for vertical deployment.|
|25P.xxx4||No cage||Sensors, cables, & plumbing are not integrated, but all parts are provided. This selection may be useful for integration in your own vehicle/platform.|
|SBE 25plus Auxiliary Sensor & Integration Options|
|25p-5a||SBE 43 Dissolved Oxygen Sensor (Profiling Configuration), with XSG connector, 7000 m (cable & mount included, requires 25P.xx1)||
|25p-5b||SBE 43 Dissolved Oxygen Sensor (Profiling Configuration), with Wet-pluggable connector, 7000 m (cable & mount included, requires 25P.xx2)|
|25p-5c||SBE 43 Dissolved Oxygen Sensor (Profiling Configuration), with XSG connector, 600 m plastic (cable & mount included, requires 25P.xx1)|
|25p-5d||SBE 43 Dissolved Oxygen Sensor (Profiling Configuration) with Wet-pluggable connector, 600 m plastic (cable & mount included, requires 25P.xx2)|
|25p-6a||SBE 18 pH sensor, with XSG connector, 1200 meter (cable and mount included; requires 25P.xx1)|
SBE 27 pH/ORP sensor, with AG connector, 1200 meter (cable and mount included; requires 25P.xx1)
SBE 18 pH sensor, with Wet-pluggable connector, 1200 meter (cable and mount included; requires 25P.xx2)
|25p-6d||SBE 27 pH/ORP sensor, with Wet-pluggable connector, 1200 meter (cable and mount included; requires 25P.xx2)|
|YMOLD||Extra charge for Y-cable to connect two (2) or more sensors to one (1) auxiliary sensor input bulkhead connector on CTD|
|25p-7a||Underwater power/data interface module (PDIM) with XSG connectors, integrated for use with SBE 36 CTD Deck Unit or 33 Carousel Deck Unit (includes PDIM, interface cable, and mounting hardware; requires 25P.xx1)||
SBE 36 CTD Deck Unit & PDIM provide surface power & real-time data acquisition & control for 25plus, allowing deployment with 10,000 m long single-conductor sea cables. SBE 36 is installed on ship, while PDIM is mounted on or near 25plus. See SBE 36 description for more information on interface.
|25p-7b||Underwater power/data interface module (PDIM) with Wet-pluggable connectors, integrated for use with SBE 36 CTD Deck Unit or 33 Carousel Deck Unit (includes PDIM, interface cable, and mounting hardware; requires 25P.xx2)|
|SBE 25plus Spares & Accessories|
|SBE 25 stainless steel protective cage only (no mounts) (DN 20310)||50308 cage comes standard with 25plus; these are spares.|
|SBE 25 stainless steel protective cage (23302C) with standard sensor mounts (temp/cond/pump) (DN 41192)|
|CTD cage mounting clamp, SBE 25/19 in SBE 25 type cage (2 per cage)||Clamps mount CTD to cage and come standard with 25plus; these are spares.|
Data I/O Cable, RMG-4FS with DB-9S, 2.4 m (DN 32421)
Data I/O cable connects to 4-pin end of pump-data I/O Y-cable. Connector type (RMG or wet-pluggable) must match 25plus connector type.
2.4m test cables are used for setting up system & uploading data from memory after recovery. Applicable 20 m cable is included with 25plus; these are spares.
|801374||Data I/O cable, Wet-pluggable (MCIL-4FS) with DB-9S, 2.4 m (DN 32715)|
|801380||Data I/O cable, RMG-4FS with DB-9S, 20 m shielded (DN 31222)|
|801421||Data I/O cable, Wet-pluggable (MCIL-4FS) with DB-9S, 20 m shielded (DN 32789)|
|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.|
|SBE25plus Sealogger CTD Support Kit (XSG/AG connectors) - contains spare communication cables, C,T sensor cables, pump/data Y-cable, connectors, dummy plugs, maintenance supplies, and other mechanical spares.||
Order appropriate spares kit for connector type on 25plus:
|SBE25plus Sealogger CTD Support Kit (Wet-pluggable connectors) - contains spare communication cables, C,T sensor cables, pump/data Y-cable, connectors, dummy plugs, maintenance supplies, and other mechanical spares.|
|17709||Y-cable, Pump-Data I/O, XSG/AG connectors (DN 31551)||
Cable comes standard with SBE 25plus; this is spare. Cable connects to J7 (data I/O - pump - external power) connector on 25plus end cap.
|171883||Y-cable, Pump-Data I/O, Wet-pluggable connectors (DN 32896)|
|Universal plumbing kit (includes pump air release valve, Y-fitting, & tubing) - Application Note 64-1||Application Note 64-1 details installation of plumbing for SBE 43 & pump on a CTD.|
|Cell filler/storage device with hose barbs (Application Note 34)||For cleaning conductivity cell after each use & storing instrument between uses. See document 67043 & Application Note 2D: Instructions for Care and Cleaning of Conductivity Cells.|
|various||Plumbing||For assorted sizes of Tygon tubing, see SBE 5T Configuration.|
|31634||Hardigg shipping case (AL4915-1105)||Hardigg shipping case with custom foam inserts holds SBE 25plus with auxiliary sensors in cage (SBE 9plus shown; SBE 25plus similar).
Notes regarding features of Hardigg case supplied by Sea-Bird:
|Underwater Cable for Hand-Hauled, Real-Time Profiling (see Application Note 59 for proper use and limitations)|
|801150||Load-bearing Data cable, XSG connector with DB-9S, 100 feet (30 m) (DN 32284)||
These cables are for hand-hauling 25plus & acquiring real-time data. Cables are not intended for static working loads above 45 kg (100 lbs); working loads above 18 kg (40 lbs) may be difficult to handle without winch. Minimum recommended cable bend radius is 10 cm (4 in.) (e.g., 20 cm sheave block nominal diameter). See Application Note 59: A Load-Bearing Underwater Cable for Hand-Hauled, Real-Time Profiling.
Select a cable with connector (XSG or wet-pluggable MCBH) to match your 25plus.
|801295||Load-bearing Data cable, XSG connector with DB-9S, 165 feet (50 m) (DN 32284)|
|801140||Load-bearing Data cable, XSG connector with DB-9S, 200 feet (61 m) (DN 32284)|
|801153||Load-bearing Data cable, XSG connector with DB-9S, 330 feet (100 m) (DN 32284)|
|801301||Load-bearing Data cable, XSG connector with DB-9S, 415 feet (126 m) (DN 32284)|
|801148||Load-bearing Data cable, XSG connector with DB-9S, 600 feet (183 m) (DN 32284)|
|801371||Load-bearing Data cable, Wet-pluggable with DB-9S, 100 feet (30 m) (DN 32643)|
|801372||Load-bearing Data cable, Wet-pluggable with DB-9S, 200 feet (60 m) (DN 32643)|
|801337||Load-bearing Data cable, Wet-pluggable with DB-9S, 330 feet (100 m) (DN 32643)|
|801338||Load-bearing Data cable, Wet-pluggable with DB-9S, 660 feet (200 m) (DN 32643)|
Many cables, mount kits, and spare parts can be ordered online.
- 801380 To computer COM port (from XSG connector), shielded, 20 m, DN 31222
Note: 801380 connects to 4-pin end of Y-cable 17709.
- 801225 To computer COM port (from XSG connector), 2.4 m, DN 32421
Note: 801225 connects to 4-pin end of Y-cable 17709.
- 801421 To computer COM port (from Wet-pluggable connector), shielded, 20 m, DN 32789
Note: 801421 connects to 4-pin end of Y-cable 171883.
- 801374 To computer COM port (from Wet-pluggable connector), 2.4 m, DN 32715
Note: 801374 connects to 4-pin end of Y-cable 171883.
- Part # varies with length, To computer COM port, load-bearing cable (from XSG connector), DN 32284 (also see Application Note 59)
Note: Load-bearing cable connects to 4-pin end of Y-cable 17709.
- Part # varies with length, To computer COM port, load-bearing cable (from Wet-pluggable connector), DN 32643 (also see Application Note 59)
Note: Load-bearing cable connects to 4-pin end of Y-cable 171883.
- 17086 To SBE 3 or SBE 4 (RMG connectors), 0.64 m, DN 30566
- 171669 To SBE 3 or SBE 4 (Wet-pluggable connectors), 0.76 m, DN 32671
- 17709 To SBE 5M, 5T, or 5P (Y-cable to pump and data I/O, RMG/AG connectors), DN 31551
- 171883 To SBE 5M, 5T, or 5P (Y-cable to pump and data I/O, Wet-pluggable connectors), DN 32896
- 17595 To SBE 18 (RMG/AG connectors), 1.1 m, DN 30918
- 171828 to SBE 18 (Wet-pluggable connectors), 1.1 m, DN 32845
- 171704 To SBE 27 (AG connectors), 1.1 m, DN 31749
- 171826 To SBE 27 (Wet-pluggable connectors), 1.1 m, DN 32844
- 17292 To SBE 32 (RMG connectors), 2 m, DN 30567
- 171912 To SBE 32 (Wet-pluggable connectors), 2 m, DN 32810
- 172447 To SBE 43 (RMG/AG connectors), 1.1 m, DN 32496
- 172448 To SBE 43 (Wet-pluggable connectors), 1.1 m, DN 32654
- 172259 To SBE 55 (RMG/AG connectors), 1.2 m, DN 33191
- 172260 To SBE 55 (Wet-pluggable connectors), 1.2 m, DN 33192
- 17821 To Auto Fire Module (AFM) (RMG connectors), 1.2 m, DN 31670
- 17884 To Auto Fire Module (AFM) (RMG connectors), 1.8 m, DN 31670
- 171846 To Auto Fire Module (AFM) (Wet-pluggable connectors), 1.8 m, DN 32859
- 17088 To Power & Data Interface Module (PDIM), (RMG connectors), 1.1 m, DN 30567
- 171792 To Power & Data Interface Module (PDIM), (Wet-pluggable connectors), 1.1 m, DN 32810
- 171130 To Benthos/Datasonics PSA-916 (from AG connector), 1.8 m, DN 32075
- 17610 To Biospherical QSP-200L or QSP-2300L (from AG connector), 2 m, DN 30701
- 17342 To Biospherical QSP-200PD (from AG connector), 1.1 m, DN 30922
- 171640 To Biospherical QSP-2200 (from AG connector), 1.5 m, DN 32648
- 17602 To Chelsea AquaTracka or AlphaTracka (from AG connector), 1.2 m, DN 31253
- 17361 To D&A OBS-3 (from AG connector), 0.76 m, DN 30954
- 172130 To D&A OBS-3+ (from AG connector), High & Low range, 1 m, DN 33080
- 172131 To D&A OBS-3+ (from Wet-pluggable connector), High & Low range, 1 m, DN 33081
- 172109 To D&A OBS-3+ (from AG connector), Low range (1X), 1 m, DN 33058
- 172111 To D&A OBS-3+ (from Wet-pluggable connector), Low range (1X), 1 m, DN 33060
- 172110 To D&A OBS-3+ (from AG connector), High range (4X), 1 m, DN 33059
- 172112 To D&A OBS-3+ (from Wet-pluggable connector), High range (4X), 1 m, DN 33061
- 172215 To Satlantic SatPAR (from AG connector), 2 m, DN 32628
- 172214 To Satlantic SatPAR (from Wet-pluggable connector), 2 m, DN 32654
- 171099 To Seapoint fluorometer or turbidity meter (1X) (from V2 AG connector), 1.1 m, DN 32073
- 171147 To Seapoint fluorometer or turbidity meter (3X/5X) (from AG connector), 1.1 m, DN 32101
- 172221 To Seapoint fluorometer or turbidity meter (10X/20X) (from AG connector), 1.1 m, DN 31933
- 171845 To Seapoint fluorometer or turbidity meter (30X/100X) (from AG connector), 1.1 m, DN 31924
- 171908 To Turner Cyclops-7 (1X) (from AG connector), 1.1 m, DN 32910
- 171907 To Turner Cyclops-7 (10X) (from AG connector), 1.1 m), DN 32909
- 171909 To Turner Cyclops-7 (100X) (from AG connector), 1.1 m, DN 32911
- 171418 To Turner SCUFA (from AG connector), 1.1 m, DN 32417
- 17876 To WET Labs C-Star or WETStar with old-style 4-pin connector (from AG connector), 1.1 m, DN 31725
- 171953 To WET Labs ECO-AFL, ECO-FL, C-Star, or WETStar with new-style 6-pin connector (from AG connector), 1.1 m, DN 32491
- 172437 To WET Labs ECO-AFL, ECO-FL, C-Star, or WETStar with new-style 6-pin connector (from Wet-pluggable connector), 1.1 m, DN 32853
- 171869 To WET Labs ECO-FL-NTUS or ECO-FL-NTU(RT) (from AG connector), 1.1 m, DN 32812
- 172285 To WET Labs ECO-FL-NTUS or ECO-FL-NTU(RT) (from Wet-pluggable connector), 1.1 m, DN 32846
- 173083 To WET Labs Triplet or Triplet-W (from AG connector), 1.1 m, DN 33797
- 173088 To WET Labs Triplet or Triplet-W (from Wet-pluggable connector), 1.1 m, DN 33802
To SBE 32
50121 SeaCAT/Sealogger/AFM to SBE 32 Bottle Position Mount Kit (document 67020)
To SBE 55
50422 SBE 55 Universal CTD / Electronics Installation Kit (document 67179)
- 802113 12-cell Alkaline battery pack (alkaline D-cell batteries not included)
Hardware & O-ring Kits
- 50246 Conductivity disconnect fitting spare O-ring kit
- 90199 CTD plumbing kit (document 67022)
- 90088 CTD plumbing & TC duct tubing kit (document 67018)
- 90085 TC duct & plumbing kit (document 67051)
- 23155.1 Plunger switch assembly
- 50507 Small hardware & O-ring kit for SBE 25plus (document 67221)
- 50509 Support kit for SBE 25plus with XSG/AG connectors (hardware, O-rings, cables, connectors, dummy plugs, zinc anodes, etc.) (document 67223)
- 50508 Support kit for SBE 25plus with wet-pluggable connectors (hardware, O-rings, cables, connectors, dummy plugs, zinc anodes, etc.) (document 67222)
- 23302C SBE 25 stainless steel protective cage
Compare Profiling CTDs (Conductivity, Temperature, and Pressure)
|SBE||Sampling Rate||Channels for Auxiliary Sensors||Memory||Power||Real-Time Data||Comments|
|SBE 911plus CTD (9plus CTD & 11plus Deck Unit)||24 Hz||
|16 Mb with optional SBE 17plus V2||
(with optional SBE 17plus V2)
|World's most accurate, high resolution CTD, premium sensors, multi-parameter support, water sampler control.|
|SBE 25plus Sealogger CTD||16 Hz||8 A/D;
May require SBE 36 CTD Deck Unit & PDIM
|High-resolution logging CTD with multi-parameter support. Water sampler control with SBE 33 Carousel Deck Unit.|
|SBE 25 Sealogger CTD
||8 Hz||7 A/D||8 Mb||
May require SBE 36 CTD Deck Unit & PDIM
|Replaced by SBE 25plus in 2012. Water sampler control with SBE 33 Carousel Deck Unit.|
|SBE 19plus V2 SeaCAT Profiler CTD||4 Hz||6 A/D;
May require SBE 36 CTD Deck Unit & PDIM
|Personal CTD, small, self-contained, adequate resolution. Water sampler control with SBE 33 Carousel Deck Unit.|
|SBE 19plus SeaCAT Profiler CTD
||4 Hz||4 A/D; optional PAR||8 Mb||
May require SBE 36 CTD Deck Unit & PDIM
|Replaced by SBE 19plus V2 in 2008. Water sampler control with SBE 33 Carousel Deck Unit.|
|SBE 19 SeaCAT Profiler CTD
||2 Hz||4 A/D||1 - 8 Mb||
May require SBE 36 CTD Deck Unit & PDIM
|Replaced by SBE 19plus in 2001. Water sampler control with SBE 33 Carousel Deck Unit.|
|SBE 49 FastCAT CTD Sensor||16 Hz||
May require SBE 36 CTD Deck Unit & PDIM
|For towed vehicle, ROV, AUV, or other autonomous profiling applications. Water sampler control with SBE 33 Carousel Deck Unit.|
|SBE 52-MP Moored Profiler CTD & (optional) Dissolved Oxygen Sensor||1 Hz||1 frequency channel for dissolved oxygen sensor||28,000 samples||Intended for moored profiling applications on device that is winched up and down from a buoy or bottom-mounted platform.|
|SBE 41/41CP CTD Module for Autonomous Profiling Floats (Argo)||OEM CTD for sub-surface oceanographic float that surfaces at regular intervals, transmits new drift position and in situ measurements to ARGOS satellite system. CTD obtains latest temperature and salinity profile for transmission on each ascent. Also available is a Navis Autonomous Profiling Float, Navis BGCi Autonomous Profiling Float with Integrated Biogeochemical Sensors, and Navis BGCi + pH Autonomous Profiling Float with Integrated Biogeochemical Sensors|
|Glider Payload CTD (GPCTD) and Slocum Glider Payload CTD||OEM CTD for autonomous gliders. Generic Glider Payload CTD (GPCTD) is modular, low-power profiling instrument that measures C, T, P, and (optional) Dissolved Oxygen. Slocum Glider Payload CTD provides retrofit/replacement for CTDs on Slocum gliders. Designs share many features, but there are differences in packaging, sampling abilities, power consumption, and installation (see individual data sheets).|
1. See Application Note 82: Guide to Specifying a CTD.
2. products are no longer in production. Follow the links above to the product page to retrieve manuals and application notes for these older products.