Frequently Asked Questions (FAQs) --
Service

FAQs have been organized into the following categories:

Service questions (this page)

• How often do I need to have my instrument and/or auxiliary sensors recalibrated? Can I recalibrate them myself?
• I am planning to ship my instrument to Sea-Bird for calibration and minor repairs. What is the typical turn-around time?
• I am planning to ship my instrument to Sea-Bird for calibration and minor repairs. Should I also send the auxiliary sensors from other manufacturers?
• My auxiliary sensor (not manufactured by Sea-Bird) needs to be repaired / recalibrated. Where should I send it for servicing?
• I want to add an auxiliary sensor to my CTD. Assuming the auxiliary sensor is compatible with the instrument, what is the procedure?
• Do I need to remove batteries before shipping my instrument for a deployment or to Sea-Bird?
• Do I need to clean the exterior of my instrument before shipping it to Sea-Bird for calibration?
• 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?
• Can I brush clean and replatinize the conductivity cell myself? How often should this be done?
• 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?
• How can I tell if the conductivity cell on my CTD is broken?
• What are Configuration Sheets, and where can I find them for my instrument?
• What is Sea-Bird's policy on upgrading instruments?
• Should I purchase spare pressure sensors for my SBE 9plus?
• What do I need to send to Sea-Bird for calibration of my SBE 9plus?
• What do I need to send to Sea-Bird for calibration of my SBE 25 or 25plus?
• Does Sea-Bird have any calibration/service centers outside of the United States?

Note: See Service & Calibration for additional information.

	General instrument questions How do instruments handle external power if internal batteries are installed? What is the maximum cable length for real-time RS-232 data? Why do some instruments have zinc anodes, while others do not? Do Anti-Foulant Devices affect the conductivity cell calibration? What is Triton? Does it harm sensors? Do I need to purchase it from Sea-Bird? Where can I get information about safe handling/hazards associated with chemicals used with Sea-Bird equipment, such as Anti-Foulant Devices and Triton X-100 detergent? Why is Teflon tape used? My CTD has a Digiquartz pressure sensor. Can I use it above its rated pressure? My CTD has a Druck pressure sensor. Can I use it above its rated pressure? What do you recommend for cleaning barnacles off the exterior of the instrument? Why is the color on my instrument housing changing? Can I use hydrochloric acid to clean the outside of the housing? Why am I getting negative density values when testing the instrument? What is a wet-pluggable or wet-mateable or MCBH connector? Can I mate and unmate a cable with this connector underwater? Do you recommend a particular brand of alkaline D-cell batteries?
	General oceanographic questions What is the difference between psu and ppt? Is the salinity calculated by Sea-Bird valid above 42 psu? Does Sea-Bird software output Practical Salinity (psu) or Absolute Salinity? What is the difference between IPTS-68 and ITS-90? What is the difference between initial accuracy and resolution? Why is sound velocity (SV) computed from a CTD better than sound velocity from direct measuring instruments? Which algorithm for calculating sound velocity (SV) from CTD data should I use? What is hydrostatic head effect? How can I find the density of seawater at different temperatures and/or salinities? What is the cause of conductivity drift? Does it matter whether you use natural or artificial seawater for calibrations? Which does Sea-Bird use? Where can I purchase standard seawater? Why is my CTD data showing hysteresis?
	Recommended practices What are the major steps involved in taking a cast with a Profiling CTD? Should I collect water samples (close bottles) on the downcast or the upcast? Can I deploy my profiling CTD for monitoring an oil spill? What are the major steps involved in deploying a moored instrument? What are the recommended practices for mating and unmating connectors? How can I tell if my connectors have leaked, and what do I do about corrosion on connector pins? What are the recommended practices for replacing a bulkhead connector? What are the recommended practices for inspecting and cleaning o-rings and mating surfaces? How often should I replace o-rings? How should I handle my CTD to avoid cracking the conductivity cell? What is an Anti-Foulant Device? How often should I replace it? Does it require special handling? What are the recommended practices for deploying in frazil or pancake ice, or deploying at low temperatures? Does it matter if I deploy my moored instrument, which includes a conductivity sensor, in a horizontal or vertical position? How many / what kind of spares should I have on ship for my instrument? How many/what kind of spares should I have on ship for my SBE 9plus? How will my CTD be affected by adjacent objects? What are the safety concerns/procedures if the instrument floods? Can the instrument explode? Is it necessary to put my instrument in water to test it? Will I destroy the conductivity cell if I test it in air? How should I store my conductivity sensor if there is danger of freezing? What are the recommended practices for cleaning and lubricating winch cables? What are the recommended practices for splicing cables?
	Ordering How do I find information about the options available with each instrument? Where do I find pricing information for new instruments, calibration services, and/or repair services? Which Sea-Bird profiling CTD is best for my application? I want to integrate a moored CTD with some auxiliary sensors (transmissometer, fluorometer, etc.). Which CTD should I use? How should I pick the pressure sensor range for my CTD? Would the highest range give me the most flexibility in using the CTD? 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? What are the pros and cons of ordering wet-pluggable connectors? Can Sea-Bird provide some guidance for ordering cable, winch, and deck gear?
	Software I am confused by all these software names. Which software does what? Can I install my Sea-Bird CD-ROM on multiple computers or give it to another interested scientist? How can I copy the setup of my Sea-Bird software onto another computer? How can I view CTD data? What is a configuration (.con or .xmlcon) file and how is it used? What is a .psa file and how is it used? Does Seasoft have a provision for converting to MatLab data files? Can I use Seasoft on a Macintosh, Unix, or Linux system? Is the Windows version of Seasoft compatible with Microsoft's Vista operating system? Is the Windows version of Seasoft compatible with Microsoft's Windows 7 operating system? Your website Download Software from FTP Site page defines the latest software revision, but I cannot find the latest revision on the FTP site. Is it not posted yet? Why am I having trouble downloading software from your FTP site? How does Sea-Bird software calculate conductivity, temperature, and pressure in engineering units? How does Sea-Bird software calculate derived variables such as salinity, sound velocity, density, depth, thermosteric anomaly, specific volume, potential temperature, etc.? What is the flag variable column that is added to the data file by SBE Data Processing's Data Conversion or ASCII In module? What formula does Sea-Bird software use to convert pressure data to depth? In Sea-Bird software, is noon on January 1 Julian Day 0.5 or Julian Day 1.5? Can I edit my .dat data file to add some explanatory notes to header? Can I edit my .hex data file to add some explanatory notes to header? Why am I getting a class not registered error when running SBE Data Processing?
	Data analysis and processing Why and how should I align data from a 911plus CTD? What are the typical data processing steps recommended for each instrument? Where can I find formulas for calculating conductivity, temperature, pressure, and derived parameters such as salinity, sound velocity, density, depth, thermosteric anomaly, specific volume, potential temperature, etc.?
	Manufacturing Does Sea-Bird pressure test each instrument before shipping to verify integrity of housing, o-rings, assembly, etc.? Does Sea-Bird check and calibrate all sensors on a CTD system prior to shipping? Do Sea-Bird instruments have CE certification? Do Sea-Bird instruments have ISO certification?

Our Glossary page is another good source of information.

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 and training. 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)
  - SBE 13/23 (no longer in production) -- recalibrate every 6 months
• 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.

Typically, Sea-Bird can calibrate the instrument and perform minor repairs within 3 - 4 weeks, plus shipping time. However, this may vary, depending on current backlog. Before shipping an instrument to us, obtain an RMA number (email seabird@seabird.com or call 425-643-9866) and fill out a Service Request Form, so that we know your instrument is on the way and can schedule appropriately. If time is critical, contact us before shipping to verify that we can meet your schedule.

Notes:

• The typical 3 - 4 week turnaround does not apply to recalibrating / repairing auxiliary sensors produced by other manufacturers. Recalibration / repair of these sensors must be performed by the manufacturers. See My auxiliary sensor needs to be repaired / recalibrated below for details.
• Sea-Bird opened a calibration and repair center in Germany in 2011, which can provide faster shipping for European customers.

The answer to this question depends on your budget and your level of confidence that the entire system is functioning properly. When Sea-Bird receives CTDs that have integrated auxiliary sensors produced by other manufacturers, we test the functionality of the entire system. For a standard charge, we:

• Visually inspect the physical condition of the auxiliary sensor, connector, and interface cable.
• Visually inspect the mounting scheme of the auxiliary sensor on the CTD (a poor mounting scheme can result in poor data).*
• (For voltage sensors) Measure the open voltage and block voltage to ensure that the auxiliary sensor responds through the full 0 - 5V range.
• Check that the auxiliary sensor reads correctly when submerged in our cold salt water test baths for 30 - 60 minutes.

If the auxiliary sensor does not meet our standards*, we recommend that the sensor be sent to the other manufacturer for service. If the sensor is sent to the other manufacturer, we perform the same tests when it returns to us after servicing. Additionally, we update the configuration (.con or .xmlcon) file with any new calibration coefficients.

*Note: Sea-Bird can fix mounting scheme issues; we do not send the sensor to the other manufacturer for this.

Sea-Bird does not repair or recalibrate other manufacturers’ instruments that have been integrated with Sea-Bird equipment. If an auxiliary sensor needs to be repaired or recalibrated, we recommend that you send it directly to the manufacturer. If you send it to Sea-Bird, we will have to send it to the manufacturer, resulting in additional shipping (and possibly customs) expenses for you.

Note: Apparent malfunctioning of an auxiliary sensor can be caused by many things, including incorrect configuration (.con or .xmlcon) file, incorrect instrument setup, incorrect or leaky cables, poor mounting scheme, etc.

• If you are not certain that the auxiliary sensor needs to be repaired, Sea-Bird can help you troubleshoot the system by phone or e-mail at no charge.
• Alternatively, if you ship us the entire system, we can troubleshoot at the factory for our standard charges (see the FAQ above this for troubleshooting description). If we determine that the auxiliary sensor does need to be repaired, we will coordinate with you on shipment of the sensor to the manufacturer.

Adding the sensor(s) is reasonably straightforward:

1. 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.).
2. Attach the new cable.
3. (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.
4. 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.

With the following exceptions, the instrument can be shipped with the batteries installed in the housing.

Exceptions:

• SBE 37-IM, IMP, IMP-IDO, IMP-ODO, SM, SMP, SMP-IDO, and SMP-ODO MicroCAT, and SBE 44 Underwater Inductive Modem

Sea-Bird ships these batteries outside of the instrument, not assembled in the battery pack, in a heat-sealed bag placed in bubble wrap and inside strong packaging. See the instrument manual for packing and labeling details.

If two or more of these battery sticks are assembled into the instrument’s battery pack (either inside or outside the instrument housing), they are connected in parallel and are classified as Dangerous/Hazardous Goods. The assembled battery pack does not comply with regulations requiring battery packaging test documentation and therefore MUST NOT BE SHIPPED VIA COMMERCIAL AIRCRAFT, INCLUDING PASSENGER AIRLINES, OR CARGO CARRIERS SUCH AS FEDEX, DHL, UPS, ETC.

DO NOT RETURN THESE USED LITHIUM BATTERIES TO SEA-BIRD. Remove the batteries from the instrument prior to shipping to Sea-Bird. If you send the batteries to Sea-Bird, we will package, label, and document them properly and return them to you. The costs for this work are not insignificant, and we will charge you a fee for handling.

• SBE 16plus, 16plus-IM, 16plus V2, 16plus-IM V2, and 26 with Optional Electro Chem Lithium Batteries

As of 2004, Sea-Bird no longer ships Electro Chem lithium batteries, due to changes in U.S. DOT and IATA regulations. If shipping Electro Chem cells or batteries by commercial carrier, transport them in accordance with DOT and IATA regulations. Sea-Bird cannot advise you on this matter; consult the proper authorities.

If you will be shipping your instrument to Sea-Bird for servicing or calibration, DO NOT RETURN ELECTRO CHEM LITHIUM BATTERIES TO SEA-BIRD. Remove and store the batteries for future use, or dispose of properly. If you send the batteries to Sea-Bird, we will not ship them back to you. If you cannot arrange for pick-up of the batteries at our factory, we will dispose of the batteries for you. The costs for disposal are not insignificant, and we will charge you a fee for handling.

Remove as much biological material and/or anti-foul coatings as possible before shipping. Sea-Bird cannot place an instrument with a large amount of biological material or anti-foul coating on the housing in our calibration bath; if we need to clean the exterior before calibration, we will charge you for this service.

• To remove barnacles, plug the ends of the conductivity cell to prevent the cleaning solution from getting into the cell. Then soak the entire instrument in white vinegar for a few minutes. After scraping off the barnacles and marine growth, rinse the instrument well with fresh water.
• To remove anti-foul paint, use a Heavy Duty Scotch-Brite pad (http://www.3m.com/us/home_leisure/scotchbrite/products/scrubbing_scouring.html) or similar scrubbing device.

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:

1. 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.
2. 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.
3. 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.
4. For the most demanding work, calibrate the sensor on a deadweight tester to ensure proper operation and calibration.
5. 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, 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.

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.

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.

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 for details on connector care and 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.

Configuration Sheets detail instrument communication settings, system configuration (auxiliary sensors, which channels are set up for which sensors), and sensor calibration coefficients. Configuration sheets are provided with the instrument, in both paper form (may be part of the manual) and on the CD-ROM.

Configuration Sheet location varies, depending on the type of instrument and when it was shipped:

It is our policy to update firmware in instruments while they are here for calibration at no cost to the customer, but it is not our policy to routinely upgrade circuit cards. On some very old units that are being upgraded to support more external sensors, new pressure sensors, or other repairs, we sometimes discount the new circuit cards as part of the larger upgrade, as that makes the work easier for us to complete.

Most SBE 9plus users do not purchase spare pressure sensors for the following reasons:

• The pressure sensor is inside the SBE 9plus 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.

It is much more common to purchase spare conductivity and temperature sensors. These are the sensors more exposed to ocean conditions and therefore more likely to be broken. It is also very easy to change them because they are independent sensors that plug into the SBE 9plus main housing.

• 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 SBE 9plus main housing. See Removing Temperature and Conductivity Sensors for Calibration for details.
• It is usually not necessary to recalibrate the Digiquartz pressure sensor. Long 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. Generally, the offset drift is only 0.01% to 0.02% per year. 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). However, if the sensor does need to be calibrated, the entire CTD must be shipped to Sea-Bird.

SBE 25: For calibration of the temperature, conductivity, and/or pressure sensors, only the sensor modules need to be sent to Sea-Bird. It is not necessary to send the SBE 25 main housing. See Removing Temperature and Conductivity Sensors for Calibration for details.

SBE 25plus: For calibration of the temperature and/or conductivity sensors, only the sensor modules need to be sent to Sea-Bird. It is not necessary to send the SBE 25plus main housing. See Removing Temperature and Conductivity Sensors for Calibration for details.

Sea-Bird opened a calibration/service center in Kempten, Germany in 2011. Details.

Sea-Bird Home     Phone: (+1) 425-643-9866     E-mail: seabird@seabird.com