Sea-Bird Electronics SBE 49 FastCAT Specifications

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APPLICATION NOTES
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APPLICATION NOTES

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Sea-Bird Electronics, Inc.
1808 136th Place NE
Bellevue, WA 98005
USA
Phone: (425) 643-9866
Fax: (425) 643-9954
E-mail: seabird@seabird.com
Web: www.seabird.com
APPLICATION NOTE NO. 2D
Revised October 2006
Instructions for Care and Cleaning of Conductivity Cells
This application note presents new recommendations, based on our recent research, for cleaning and storing
conductivity sensors. In the past, Sea-Bird had recommended cleaning and storing conductivity sensors with a Triton
X-100 solution, and cleaning conductivity sensors with an acid solution. Our latest research leads us to recommend
adding the use of a dilute bleach solution to eliminate growth of bio-organisms, and eliminating the use of acid in
most cases.
The application note is divided into three sections:
General discussion
Rinsing, cleaning, and storage procedures
Cleaning materials
General Discussion
Since any conductivity sensor’s output reading is proportional to its cell dimensions, it is important to keep the cell
clean of internal coatings. Also, cell electrodes contaminated with oil, biological growths, or other foreign material will
cause low conductivity readings. A desire to provide better control of growth of bio-organisms in the conductivity cell
led us to develop revised rinsing and cleaning recommendations.
A dilute bleach solution is extremely effective in controlling the growth of bio-organisms in the conductivity
cell. Lab testing at Sea-Bird over the past year indicates no damaging effect from use of a dilute bleach
solution in cleaning the conductivity cell. Sea-Bird now recommends cleaning the conductivity sensor in a
bleach solution.
Triton X-100 is a mild, non-ionic surfactant (detergent), valuable for removal of surface and airborne oil
ingested into the CTD plumbing as the CTD is removed from the water and brought on deck. Sea-Bird had
previously recommended, and continues to recommend, rinsing and cleaning the conductivity sensor in a
Triton solution.
Sea-Bird had previously recommended acid cleaning for eliminating bio-organisms or mineral deposits on
the inside of the cell. However, bleach cleaning has proven to be effective in eliminating growth of bioorganisms; bleach is much easier to use and to dispose of than acid. Furthermore, data from many years of
use shows that mineral deposits are an unusual occurrence. Therefore, Sea-Bird now recommends that, in
most cases, acid should not be used to clean the conductivity sensor. In rare instances, acid cleaning may
still be required for mineral contamination of the conductivity cell. Sea-Bird recommends that you return
the equipment to the factory for this cleaning if it is necessary.
Sea-Bird had previously recommended storing the conductivity cell filled with water to keep the cell wetted, unless the
cell was in an environment where freezing is a possibility (the cell could break if the water freezes). However, no
adverse affects have been observed as a result of dry storage, if the cell is rinsed with fresh, clean water before storage
to remove any salt crystals. This leads to the following revised conductivity cell storage recommendations:
Short term storage (less than 1 day, typically between casts): If there is no danger of freezing, store the
conductivity cell with a dilute bleach solution in Tygon tubing looped around the cell. If there is danger of
freezing, store the conductivity cell dry, with Tygon tubing looped around the cell.
Long term storage (longer than 1 day): Since conditions of transport and long term storage are not always under
the control of the user, we now recommend storing the conductivity cell dry, with Tygon tubing looped around the
cell ends. Dry storage eliminates the possibility of damage due to unforeseen freezing, as well as the possibility of
bio-organism growth inside the cell. Filling the cell with a Triton X-100 solution for 1 hour before deployment will
rewet the cell adequately.
Note that the Tygon tubing looped around the ends of the conductivity cell, whether dry or filled with a bleach or Triton
solution, has the added benefit of keeping air-borne contaminants (abundant on most ships) from entering the cell.
1

Rinsing, Cleaning, and Storage Procedures
SBE 4 Conductivity Sensor
Note: See Cleaning Materials below for discussion of appropriate
sources / concentrations of water, Triton X-100, bleach, and tubing.
Soaker tube
CAUTIONS:
The conductivity cell is primarily glass, and can break if
mishandled. Use the correct size Tygon tubing; using tubing with a smaller ID will make it difficult to remove the
tubing, and the cell end may break if excessive force is used. The correct size tubing for use in cleaning / storing
all conductivity cells produced since 1980 is 7/16" ID, 9/16" OD. Instruments shipped prior to 1980 had smaller
retaining ridges at the ends of the cell, and 3/8" ID tubing is required for these older instruments.
Do not put a brush or object (e.g., Q-Tip) inside the conductivity cell to clean it or dry it. Touching and
bending the electrodes can change the calibration; large bends and movement of the electrodes can damage the
cell.
If an SBE 43 dissolved oxygen (DO) sensor is plumbed to the CTD - Before soaking the conductivity cell for
more than 1 minute in Triton X-100 solution, disconnect the tubing between the conductivity cell and DO
sensor to prevent extended Triton contact with the DO sensor membrane (extended Triton contact can damage the
membrane). See Application Note 64 for rinsing, cleaning, and storage recommendations for the SBE 43.
Active Use (after each cast)
1.
2.
Rinse: Remove the plumbing (Tygon tubing) from the exhaust end of the conductivity cell. Flush the cell with a
0.1% Triton X-100 solution. Rinse thoroughly with fresh, clean water and drain.
If not rinsed between uses, salt crystals may form on the conductivity cell platinized electrode surfaces. When
the instrument is used next, sensor accuracy may be temporarily affected until these crystals dissolve.
Store: The intent of these storage recommendations is to keep contamination from aerosols and spray/wash on the
ship deck from harming the sensor’s calibration.
No danger of freezing: Fill the cell with a 500 – 1000 ppm bleach solution, using a length of Tygon tubing
attached to each end of the conductivity sensor to close the cell ends.
Danger of freezing: 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.
Routine Cleaning (no visible deposits or marine growths on sensor)
1.
2.
Agitate a 500 – 1000 ppm Bleach solution warmed to 40 C through the cell in a washing action (this can be
accomplished with Tygon tubing and a syringe kit – see Application Note 34) for 2 minutes. Drain and flush
with warm (not hot) fresh, clean water for 5 minutes.
Agitate a 1%-2% Triton X-100 solution warmed to 40 C through the cell many times in a washing action
(this can be accomplished with Tygon tubing and a syringe kit). Fill the cell with the solution and let it soak for
1 hour. Drain and flush with warm (not hot) fresh, clean water for 5 minutes.
Cleaning Severely Fouled Sensors (visible deposits or marine growths on sensor)
Repeat the Routine Cleaning procedure up to 5 times.
Long-Term Storage (after field use)
1.
2.
3.
Rinse: Remove the plumbing (Tygon tubing) from the exhaust end of the conductivity cell. Flush the cell with a
0.1% Triton X-100 solution. Rinse thoroughly with fresh, clean water and drain. Remove larger droplets of
water by blowing through the cell. Do not use compressed air, which typically contains oil vapor.
Store: Attach a length of Tygon tubing to each end of the conductivity cell to close the cell ends. The loop prevents
any contaminants from entering the cell.
Storing the cell dry prevents the growth of any bio-organisms, thus preserving the calibration.
When ready to deploy again: Fill the cell with a 0.1% Triton X-100 solution for 1 hour before deployment. Drain
the Triton X-100 solution; there is no need to rinse the cell.
2

Cleaning Materials
Water
De-ionized (DI) water, commercially distilled water, or fresh, clean, tap water is recommended for rinsing, cleaning,
and storing sensors.
On ships, fresh water is typically made in large quantities by a distillation process, and stored in large tanks.
This water may be contaminated with small amounts of oil, and should not be used for rinsing, cleaning, or
storing sensors.
Where fresh water is in extremely limited supply (for example, a remote location in the Arctic), you can substitute
clean seawater for rinsing and cleaning sensors. If not immediately redeploying the instrument, follow up with a
brief fresh water rinse to eliminate the possibility of salt crystal formation (salt crystal formation could cause small
shifts in calibration).
The seawater must be extremely clean, free of oils that can coat the conductivity cell. To eliminate any bioorganisms in the water, Sea-Bird recommends boiling the water or filtering it with a 0.5 micron filter.
Triton X-100
Triton X-100 is Octyl Phenol Ethoxylate, a mild, non-ionic surfactant (detergent). Triton X-100 is included with
every CTD shipment and can be ordered from Sea-Bird, but may be available locally from a chemical supply
or lab products company. It is manufactured by Mallinckrodt Baker (see
http://www.mallbaker.com/changecountry.asp?back=/Default.asp for local distributors). Other liquid detergents can
probably be used, but scientific grades (with no colors, perfumes, glycerins, lotions, etc.) are required because of their
known composition. It is better to use a non-ionic detergent, since conductivity readings taken immediately after use are
less likely to be affected by any residual detergent left in the cell.
100% Triton X-100 is supplied by Sea-Bird; dilute the Triton as directed in Rinsing, Cleaning, and Storage
Procedures.
Bleach
Bleach is a common household product used to whiten and disinfect laundry. Commercially available bleach is
typically 4 % - 7% (40,000 – 70,000 ppm) sodium hypochlorite (Na-O-Cl) solution that includes stabilizers. Some
common commercial product names are Clorox (U.S.) and eau de Javel (French).
Dilute to 500 – 1000 ppm. For example, if starting with 5% (50,000 ppm) sodium hypochlorite, diluting 50 to 1
(50 parts water to 1 part bleach) yields a 1000 ppm (50,000 pm / 50 = 1000 ppm) solution.
Tygon Tubing
Sea-Bird recommends use of Tygon tubing, because it remains flexible over a wide temperature range and with age.
Tygon is manufactured by Saint-Gobain (see www.tygon.com). It is supplied by Sea-Bird, but may be available locally
from a chemical supply or lab products company.
Keep the Tygon in a clean place (so that it does not pick up contaminants) while the instrument is in use.
3

Acid
In rare instances, acid cleaning is required for mineral contamination of the conductivity cell. Sea-Bird
recommends that you return the equipment to the factory for this cleaning. Information below is provided if you
cannot return the equipment to Sea-Bird.
CAUTIONS:
SBE 37-IMP, 37-SMP, or 37-SIP MicroCAT; SBE 49 FastCAT; or other instruments with an integral,
internal pump - Do not perform acid cleaning. Acid cleaning may damage the internal, integral pump.
Return these instruments to Sea-Bird for servicing if acid cleaning is required.
SBE 9plus or SBE 25 CTD – Remove the SBE 4 conductivity cell from the CTD and remove the TC Duct
before performing the acid cleaning procedure.
All instruments which include AF24173 Anti-Foulant Devices – Remove the AF24173 Anti-Foulant
Devices before performing the acid cleaning procedure. See the instrument manual for details and handling
precautions when removing AF24173 Anti-Foulant Devices.
WARNING! Observe all precautions for working with strong acid. Avoid breathing acid fumes. Work in
a well-ventilated area.
The acid cleaning procedure for the conductivity cell uses approximately 50 - 100 cc of acid. Sea-Bird recommends
using a 20% concentration of HCl. However, acid in the range of 10% to full strength (38%) is acceptable.
If starting with a strong concentration of HCl that you want to dilute:
For each 100 cc of concentrated acid, to get a 20% solution, mix with this amount of water Water = [(conc% / 20%) – 1 ] * [100 + 10 (conc% / 20% )] cc
Always add acid to water; never add water to acid.
Example -- concentrated solution 31.5% that you want to dilute to 20%:
[(31.5% / 20%) – 1 ] * [100 + 10 (31.5% / 20% )] = 66.6 cc of water.
So, adding 100 cc of 31.5% HCl to 66.6 cc of water provides 166.6 cc of the desired concentration.
For 100 cc of solution:
100 cc * (100 / 166.6) = 60 cc of 31.5% HCl
66.6 cc * (100 / 166.6) = 40 cc of water
For acid disposal, dilute the acid heavily or neutralize with bicarbonate of soda (baking soda).
1.
2.
3.
Prepare for cleaning:
A. Place a 0.6 m (2 ft) length of Tygon tubing over the end of the cell.
B. Clamp the instrument so that the cell is vertical, with the Tygon tubing at the bottom end.
C. Loop the Tygon tubing into a U shape, and tape the open end of the tubing in place at the same height
as the top of the glass cell.
Clean the cell:
A. Pour 10% to 38% HCl solution into the open end of the tubing until the cell is nearly filled. Let it
soak for 1 minute only.
B. Drain the acid from the cell and flush for 5 minutes with warm (not hot), clean, de-ionized water.
C. Rinse the exterior of the instrument to remove any spilled acid from the surface.
D. Fill the cell with a 1% Triton X-100 solution and let it stand for 5 minutes.
E. Drain and flush with warm, clean, de-ionized water for 1 minute.
F. Carefully remove the 0.6 m (2 ft) length of Tygon tubing.
Prepare for deployment, or follow recommendations above for storage.
4

Sea-Bird Electronics, Inc.
1808 136th Place NE
Bellevue, WA 98005
USA
APPLICATION NOTE NO. 6
Phone: (425) 643-9866
Fax: (425) 643-9954
E-mail: seabird@seabird.com
Web: www.seabird.com
Revised August 2004
DETERMINATION OF SOUND VELOCITY FROM CTD DATA
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              

and
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


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

                

            
        



            
                  

          
          

               

   






            
    It is unrealistic to expect that commercial direct-measurement
instruments will be more accurate under field conditions than the laboratory equipment used by
successions of careful researchers.

  accuracy        
  precision         




            
              

              





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           

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                 

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
Sea-Bird Electronics, Inc.
1808 136th Place NE
Bellevue, WA 98005
USA
Phone: (425) 643-9866
Fax: (425) 643-9954
E-mail: seabird@seabird.com
Web: www.seabird.com
APPLICATION NOTE NO. 10
Revised July 2005
COMPRESSIBILITY COMPENSATION OF SEA-BIRD CONDUCTIVITY SENSORS
Sea-Bird conductivity sensors provide precise characterization of deep ocean water masses. To achieve the accuracy
of which the sensors are capable, an accounting for the effect of hydrostatic loading (pressure) on the conductivity
cell is necessary. Conductivity calibration certificates show an equation containing the appropriate pressuredependent correction term, which has been derived from mechanical principles and confirmed by field observations.
The form of the equation varies somewhat, as shown below:
SBE 4, 9, 9plus, 16, 19, 21, 25, 26, 26plus, and 53 BPR
( g + h f 2 + i f 3 + j f 4 ) / 10
Conductivity (Siemens/meter) = slope
or
Conductivity (Siemens/meter) = slope
1 + [CTcor] t + [CPcor] p
(a f m + b f 2 + c + dt ) / 10
1 + [CPcor] p
+ offset
(recommended)
+ offset
SBE 16plus, 19plus, 37, 45, 49, and 52-MP
Conductivity (Siemens/meter) = slope
g + hf2 + if3 + jf4
1 + [CTcor] t + [CPcor] p
+ offset
where
a, b, c, d, m, and CPcor are the calibration coefficients used for older sensors (prior to January 1995).
Sea-Bird continues to calculate and print these coefficients on the calibration sheets for use with old
software, but recommends use of the g, h, i, j, CTcor, CPcor form of the equation for most accurate results.
g, h, i, j, CTcor, and CPcor are the calibration coefficients used for newer sensors.
Note: The SBE 26, 26plus, and 53 BPR use the SBE 4 conductivity sensor, so both sets of calibration
coefficients are reported on the calibration sheet. SEASOFT for Waves for DOS, which can be used with
the SBE 26 only, only supports use of the a, b, c, d, CTcor, and CPcor coefficients. The current processing
software for these instruments, SEASOFT for Waves for Windows, only supports use of the g, h, i, j,
CTcor, CPcor coefficients.
CPcor is the correction term for pressure effects on conductivity (see below for discussion)
slope and offset are correction coefficients used to make corrections for sensor drift between calibrations;
set to 1.0 and 0 respectively on initial calibration by Sea-Bird (see Application Note 31 for details on
calculating slope and offset)
f is the instrument frequency (kHz) for all instruments except the SBE 52-MP.
For the SBE 52-MP, f = instrument frequency (kHz) * (1.0 + WBOTC * t)0.5 / 1000.00
t is the water temperature ( C).
p is the water pressure (decibars).
Sea-Bird CTD data acquisition, display, and post-processing software SEASOFT for Waves (for SBE 26, 26plus, and
53 only) and SEASOFT (for all other instruments) automatically implement these equations.

DISCUSSION OF PRESSURE CORRECTION
Conductivity cells do not measure the specific conductance (the desired property), but rather the conductance of a
specific geometry of water. The ratio of the cell’s length to its cross-sectional area (cell constant) is used to relate the
measured conductance to specific conductance. Under pressure, the conductivity cell’s length and diameter are
reduced, leading to a lower indicated conductivity. The magnitude of the effect is not insignificant, reaching
0.0028 S/m at 6800 dbars.
The compressibility of the borosilicate glass used in the conductivity cell (and all other homogeneous, noncrystalline
materials) can be characterized by E (Young’s modulus) and (Poisson’s ratio). For the Sea-Bird conductivity cell,
E = 9.1 x 106 psi, = 0.2, and the ratio of indicated conductivity divided by true conductivity is:
1+s
where s = (CPcor) (p)
Typical value for CPcor is - 9.57 x 10-8 for pressure in decibars or - 6.60x 10-8 for pressure in psi
Note: This equation, and the mathematical derivations below, deals only with the pressure correction term, and does
not address the temperature correction term.
MATHEMATICAL DERIVATION OF PRESSURE CORRECTION
For a cube under hydrostatic load:
L / L = s = -p (1 - 2 ) / E
where
p is the hydrostatic pressure
E is Young’s modulus
is Poisson’s ratio
L / L and s are strain (change in length per unit length)
Since this relationship is linear in the forces and displacements, the relationship for strain also applies for the length,
radius, and wall thickness of a cylinder.
To compute the effect on conductivity, note that R0 = L / A , where R0 is resistance of the material at 0 pressure,
is volume resistivity, L is length, and A is cross-sectional area. For the conductivity cell A = r2 , where r is the
cell radius. Under pressure, the new length is L (1 + s) and the new radius is r (1 + s). If Rp is the cell resistance
under pressure:
Rp = L (1 + s) / ( r2 [1 + s]2) = L / r2 (1 + s) = R0 / (1 + s)
Since conductivity is 1/R:
Cp = C0 (1 + s) and C0 = Cp / (1 + s) = Cp / (1 + [Cpcor] [p])
where
C0 is conductivity at 0 pressure
Cp is conductivity measured at pressure
A less rigorous determination may be made using the material’s bulk modulus. For small displacements in a cube:
V / V = 3 L / L = -3p (1 - 2 ) / E or
V/V = -p / K
where
V / V is the change in volume per volume or volume strain
K is the bulk modulus. K is related to E and by K = E / 3 (1 - 2 ).
In this case, L / L = -p / 3K.
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                 
           
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


             


                
                 

                
               
              





Sea-Bird Electronics, Inc.
1808 136th Place NE
Bellevue, WA 98005
USA
Phone: (425) 643-9866
Fax: (425) 643-9954
E-mail: seabird@seabird.com
Web: www.seabird.com
APPLICATION NOTE 27Druck
Revised July 2005
Minimizing Strain Gauge Pressure Sensor Errors
The following Sea-Bird instruments use strain gauge pressure sensors manufactured by GE Druck:
SBE 16plus and 16plus-IM SEACAT (not 16*) with optional strain gauge pressure sensor
SBE 19plus SEACAT Profiler (not 19*)
SBE 25 SEALOGGER CTD, which uses SBE 29 Strain-Gauge Pressure Sensor (built after March 2001)
SBE 26plus SEAGAUGE Wave and Tide Recorder with optional strain gauge pressure sensor in place of
Quartz pressure sensor
SBE 37 MicroCAT (-IM, -IMP, -SM, -SMP, -SI, and -SIP) with optional pressure sensor (built after September
2000)
SBE 39 Temperature Recorder with optional pressure sensor (built after September 2000) and 39-IM Temperature
Recorder with optional pressure sensor
SBE 49 FastCAT CTD Sensor
SBE 50 Digital Oceanographic Pressure Sensor
SBE 52-MP Moored Profiler CTD and DO Sensor
* Note: SBE 16 and SBE 19 SEACATs were originally supplied with other types of pressure sensors. However, a few
of these instruments have been retrofitted with Druck sensors.
The Druck sensors are designed to respond to pressure in nominal ranges 0 - 20 meters, 0 - 100 meters, 0 - 350 meters,
0 – 600 meters, 0 – 1000 meters, 0 – 2000 meters, 0 – 3500 meters, and 0 – 7000 meters (with pressures expressed in
meters of deployment depth capability). The sensors offer an initial accuracy of 0.1% of full scale range.
DEFINITION OF PRESSURE TERMS
The term psia means pounds per square inch, absolute (absolute means that the indicated pressure is referenced to
a vacuum).
For oceanographic purposes, pressure is most often expressed in decibars (1 dbar = 1.4503774 psi). A dbar is 0.1 bar; a
bar is approximately equal to a standard atmosphere (1 atmosphere = 1.01325 bar). For historical reasons, pressure at
the water surface (rather than absolute or total pressure) is treated as the reference pressure (0 dbar); this is the value
required by the UNESCO formulas for computation of salinity, density, and other derived variables.
Some oceanographers express pressure in Newtons/meter2 or Pascals (the accepted SI unit). A Pascal is a very small
unit (1 psi = 6894.757 Pascals), so the mega-Pascal (MPa = 106 Pascals) is frequently substituted (1 MPa = 100 dbar).
Since the pressure sensors used in Sea-Bird instruments are absolute types, their raw data inherently indicate
atmospheric pressure (about 14.7 psi) when in air at sea level. Sea-Bird outputs pressure in one of the following ways:
CTDs that output raw data (SBE 16plus, 16plus-IM, 19plus, 25, and 49) and are supported by SEASOFT’s
SEASAVE (real-time data acquisition) and SBE Data Processing (data processing) software – In SEASOFT, user
selects pressure output in psi (not psia) or dbar. SEASOFT subtracts 14.7 psi from the raw absolute reading and
outputs the remainder as psi or converts the remainder to dbar.
SBE 26plus – Real-time wave and tide data is output in psia. Wave and tide data stored in memory is processed
using SEASOFT for Waves’ Convert Hex module, and output in psia. Tide data can be converted to psi by
subtracting a barometric pressure file using SEASOFT for Waves’ Merge Barometric Pressure module.
SBE 50 – User selects pressure output in psia (including atmospheric pressure) or dbar. Calculation of dbar is as
described above.
All other instruments that can output converted data in engineering units (SBE 16plus, 16plus-IM, 19plus, 37,
39, 39-IM, 49, and 52-MP) – Instrument subtracts 14.7 psi from the raw absolute reading and converts the
remainder to dbar.
Note: SBE 16plus, 16plus-IM, 19plus, 49, and 52-MP can output raw or converted data.
1

RELATIONSHIP BETWEEN PRESSURE AND DEPTH
Despite the common nomenclature (CTD = Conductivity - Temperature - Depth), all CTDs measure pressure, which is
not quite the same thing as depth. The relationship between pressure and depth is a complex one involving water
density and compressibility as well as the strength of the local gravity field, but it is convenient to think of a decibar as
essentially equivalent to a meter, an approximation which is correct within 3% for almost all combinations of salinity,
temperature, depth, and gravitational constant.
SEASOFT (most instruments)
SEASOFT offers two methods for estimating depth from pressure.
For oceanic applications, salinity is presumed to be 35 PSU, temperature to be 0o C, and the compressibility of the
water (with its accompanying density variation) is taken into account. This is the method recommended in
UNESCO Technical Paper No. 44 and is a logical approach in that by far the greatest part of the deep-ocean water
column approximates these values of salinity and temperature. Since pressure is also proportional to gravity and
the major variability in gravity depends on latitude, the user’s latitude entry is used to estimate the magnitude of the
local gravity field.
SBE 16plus, 16plus-IM, 19plus, 25, and 49 - User is prompted to enter latitude if Depth [salt water] is selected
as a display variable in SEASAVE or as an output variable in the Data Conversion or Derive module of
SBE Data Processing.
SBE 37-SM, 37-SMP, 37-IM, and 37-IMP - User is prompted to enter latitude if Depth [salt water] is selected
as an output variable in the Derive module of SBE Data Processing.
SBE 37-SI, 37-SIP, and 50 - Latitude is entered in the instrument’s EEPROM using the LATITUDE=
command in SEASOFT’s SEATERM (terminal program) software.
SBE 39 and 39-IM – User is prompted to enter latitude if conversion of pressure to depth is requested when
converting an uploaded .asc file to a .cnv file in SEATERM.
For fresh water applications, compressibility is not significant in the shallow depths encountered and is ignored, as
is the latitude-dependent gravity variation. Fresh water density is presumed to be 1 gm/cm, and depth (in meters) is
calculated as 1.019716 * pressure (in dbars). No latitude entry is required for the following:
SBE 16plus, 16plus-IM, 19plus, 25, and 49 - If Depth [fresh water] is selected as a display variable in
SEASAVE or as an output variable in the Data Conversion or Derive module of SBE Data Processing.
SBE 37-SM, 37-SMP, 37-IM, and 37-IMP - If Depth [fresh water] is selected as an output variable in the
Derive module of SBE Data Processing.
SEASOFT for Waves (SBE 26plus SEAGAUGE Wave and Tide Recorder)
SEASOFT for Waves’ Merge Barometric Pressure module subtracts a user-input barometric pressure file from the tide
data file, and outputs the remainder as pressure in psi or as depth in meters. When converting to depth, the
compressibility of the water is taken into account by prompting for user-input values for average density and gravity.
See the SBE 26plus manual’s appendix for the formulas for conversion of pressure to depth.
2

CHOOSING THE RIGHT SENSOR
Initial accuracy and resolution are expressed as a percentage of the full scale range for the pressure sensor. The
initial accuracy is 0.1% of the full scale range. Resolution is 0.002% of full scale range, except for the SBE 25
(0.015% resolution). For best accuracy and resolution, select a pressure sensor full scale range to correspond to no more
than the greatest depths to be encountered. The effect of this choice on CTD accuracy and resolution is shown below:
Range
(meters)
Maximum Initial Error
(meters)
SBE 16plus, 16plus-IM, 19plus, 37, 39, 39-IM,
49, 50, and 52-MP Resolution (meters)
SBE 25 Resolution (meters)
0 – 20
0 – 100
0 – 350
0 – 600
0 – 1000
0 - 2000
0 - 3500
0 - 7000
0.02
0.10
0.35
0.60
1.0
2.0
3.5
7.0
0.0004
0.002
0.007
0.012
0.02
0.04
0.07
0.14
0.003
0.015
0.052
0.090
0.15
0.30
0.52
1.05
Note: See the SBE 26plus manual or data sheet for its resolution specification; 26plus resolution is a function of
integration time as well as pressure sensor range.
The meaning of accuracy, as it applies to these sensors, is that the indicated pressure will conform to true pressure to
within ± maximum error (expressed as equivalent depth) throughout the sensor’s operating range. Note that a
7000-meter sensor reading + 7 meters at the water surface is operating within its specifications; the same sensor would
be expected to indicate 7000 meters ± 7 meters when at full depth.
Resolution is the magnitude of indicated increments of depth. For example, a 7000-meter sensor on an SBE 25
(resolution 1.05 meters) subjected to slowly increasing pressure will produce readings approximately following the
sequence 0, 1.00, 2.00, 3.00 (meters). Resolution is limited by the design configuration of the CTD’s A/D converter.
For the SBE 25, this restricts the possible number of discrete pressure values for a given sample to somewhat less than
8192 (13 bits); an approximation of the ratio 1 : 7000 is the source of the SBE 25’s 0.015% resolution specification.
Note: SEASOFT (and other CTD software) presents temperature, salinity, and other variables as a function of depth or
pressure, so the CTD’s pressure resolution limits the number of plotted data points in the profile. For example, an
SBE 25 with a 7000-meter sensor might acquire several values of temperature and salinity during the time required to
descend from 1- to 2-meters depth. However, all the temperature and salinity values will be graphed in clusters
appearing at either 1 or 2 meters on the depth axis.
High-range sensors used in shallow water generally provide better accuracy than their absolute specifications indicate.
With careful use, they may exhibit accuracy approaching their resolution limits. For example, a 3500-meter sensor has
a nominal accuracy (irrespective of actual operating depth) of ± 3.5 meters. Most of the error, however, derives from
variation over time and temperature of the sensor’s offset, while little error occurs as a result of changing sensitivity.
3

MINIMIZING ERRORS
Offset Errors
Note: Follow the procedures below for all instruments except the SBE 26plus (see the 26plus manual for details).
The primary offset error due to drift over time can be eliminated by comparing CTD readings in air before beginning
the profile to readings from a barometer. Follow this procedure:
1.
Allow the instrument to equilibrate in a reasonably constant temperature environment for at least 5 hours. Pressure
sensors exhibit a transient change in their output in response to changes in their environmental temperature;
allowing the instrument to equilibrate before starting will provide the most accurate calibration correction.
2.
Place the instrument in the orientation it will have when deployed.
3.
Set the pressure offset to 0.0:
In the .con file, using SEASAVE or SBE Data Processing (for SBE 16plus, 16plus-IM, 19plus, 25, or 49).
In the CTD’s EEPROM, using the appropriate command in SEATERM (for SBE 16plus, 16plus-IM, 19plus,
37, 39, 39-IM, 49, 50, or 52-MP).
4.
Collect pressure data from the instrument using SEASAVE or SEATERM (see instrument manual for details). If
the instrument is not outputting data in decibars, convert the output to decibars.
5.
Compare the instrument output to the reading from a good barometer placed at the same elevation as the pressure
sensor. Calculate offset (decibars) = barometer reading (converted to decibars) – instrument reading (decibars).
6.
Enter calculated offset (positive or negative) in decibars:
In the .con file, using SEASAVE or SBE Data Processing (for SBE 16plus, 16plus-IM, 19plus, 25, or 49).
In the CTD’s EEPROM, using the appropriate command in SEATERM (for SBE 16plus, 16plus-IM, 19plus,
37, 39, 39-IM, 49, 50, or 52-MP).
Note: For instruments that store calibration coefficients in EEPROM and also use a .con file (SBE 16plus, 16plus-IM,
19plus, and 49), set the pressure offset (Steps 3 and 6 above) in both the EEPROM and in the .con file.
Offset Correction Example
Absolute pressure measured by a barometer is 1010.50 mbar. Pressure displayed from instrument is -2.5 dbars.
Convert barometer reading to dbars using the relationship: mbar * 0.01 = dbars
Barometer reading = 1010.50 mbar *0.01 = 10.1050 dbars
Instrument’s internal calculations and/or our processing software output gage pressure, using an assumed
value of 14.7 psi for atmospheric pressure. Convert instrument reading from gage to absolute by adding 14.7
psia to instrument output: - 2.5 dbars + (14.7 psi * 0.689476 dbar/psia) = - 2.5 + 10.13 = 7.635 dbars
Offset = 10.1050 – 7.635 = + 2.47 dbar
Enter offset in .con file (if applicable) and in instrument EEPROM (if applicable).
Another source of offset error results from temperature-induced drifts. Because Druck sensors are carefully temperature
compensated, errors from this source are small. Offset errors can be estimated for the conditions of your profile, and
eliminated when post-processing the data in SBE Data Processing by the following procedure:
1.
Immediately before beginning the profile, take a pre-cast in air pressure reading.
2.
Immediately after ending the profile, take a post-cast in air pressure reading with the instrument at the same
elevation and orientation. This reading reflects the change in the instrument temperature as a result of being
submerged in the water during the profile.
3.
Calculate the average of the pre- and post-cast readings. Enter the negative of the average value (in decibars) as the
offset in the .con file.
4

Hysteresis Errors
Hysteresis is the term used to describe the failure of pressure sensors to repeat previous readings after exposure to other
(typically higher) pressures. The Druck sensor employs a micro-machined silicon diaphragm into which the strain
elements are implanted using semiconductor fabrication techniques. Unlike metal diaphragms, silicon’s crystal structure
is perfectly elastic, so the sensor is essentially free of pressure hysteresis.
Power Turn-On Transient
Druck pressure sensors exhibit virtually no power turn-on transient. The plot below, for a 3500-meter pressure sensor in
an SBE 19plus SEACAT Profiler, is representative of the power turn-on transient for all pressure sensor ranges.
Thermal Transient
Pressure sensors exhibit a transient change in their output in response to changes in their environmental temperature, so
the thermal transient resulting from submersion in water must be considered when deploying the instrument.
During calibration, the sensors are allowed to warm-up before calibration points are recorded. Similarly, for best depth
accuracy the user should allow the CTD to warm-up for several minutes before beginning a profile; this can be part of
the soak time in the surface water. Soaking also allows the CTD housing to approach thermal equilibrium (minimizing
the housing's effect on measured temperature and conductivity) and permits a Beckman- or YSI-type dissolved oxygen
sensor (if present) to polarize.
5

Sea-Bird Electronics, Inc.
1808 136th Place NE
Bellevue, WA 98005
USA
Phone: (425) 643-9866
Fax: (425) 643-9954
E-mail: seabird@seabird.com
Web: www.seabird.com
APPLICATION NOTE NO. 31
June 2006
Computing Temperature and Conductivity Slope and Offset Correction
Coefficients from Laboratory Calibrations and Salinity Bottle Samples
Conductivity Sensors
The conductivity sensor slope and offset entries in the configuration (.con) file in SEASOFT permit the user to make
corrections for sensor drift between calibrations. The correction formula is:
(corrected conductivity) = slope * (computed conductivity) + offset
where :
slope = (true conductivity span) / (instrument reading conductivity span)
offset = (true conductivity - instrument reading conductivity) * slope
measured at 0 S/m
For newly calibrated sensors, use slope = 1.0, offset = 0.0.
Sea-Bird conductivity sensors usually drift by changing span (the slope of the calibration curve), and changes are
typically toward lower conductivity readings with time. Any offset error in conductivity (error at 0 S/m) is usually due
to electronics drift, typically less than ±0.0001 S/m per year. Offsets greater than ±0.0002 S/m per year are symptomatic
of sensor malfunction. Therefore, Sea-Bird recommends that conductivity drift corrections be made by assuming
no offset error, unless there is strong evidence to the contrary or a special need.
Example
true conductivity =3.5 S/m
instrument reading conductivity = 3.49965 S/m
slope = 3.5 / 3.49965 = 1.000100
Correcting for Conductivity Drift Based on Pre- and Post-Cruise Laboratory Calibrations
Suppose a conductivity sensor is calibrated (pre-cruise), then immediately used at sea, and then returned for post-cruise
calibration. The pre- and post-cruise calibration data can be used to generate a slope correction for data obtained
between the pre- and post-cruise calibrations.
If is the conductivity computed from the pre-cruise bath data (temperature and frequency) using post-cruise
calibration coefficients and is the true conductivity in the pre-cruise bath, then:
n
( i)( i)
postslope =
i=1
(postslope is typically < 1.0)
n
( i)( i)
i=1
Sea-Bird calculates and prints the value for postslope on the conductivity calibration sheet (all calibrations since
February 1995).
1

To correct conductivity data taken between pre- and post-cruise calibrations:
islope = 1.0 + (b / n) [(1 / postslope) - 1.0]
where
islope = interpolated slope; this is the value to enter in the .con file
b = number of days between pre-cruise calibration and the cast to be corrected
n = number of days between pre- and post-cruise calibrations
postslope = slope from calibration sheet as calculated above
In the .con file, use the pre-cruise calibration coefficients and use islope for the value of slope.*
Note: The CTD configuration (.con) file is edited using the Configure menu (in SEASAVE or SBE Data Processing in
our SEASOFT-Win32 suite of programs) or the Configure Inputs menu in SEASAVE V7.
For typical conductivity drift rates (equivalent to -0.003 PSU/month), islope does not need to be recalculated more
frequently than at weekly intervals.
* You can also calculate preslope. If is the conductivity computed from post-cruise bath data (temperature and
frequency) using pre-cruise calibration coefficients and is the true conductivity in the post-cruise bath, then:
n
( i)( i)
preslope =
i=1
(preslope is typically > 1.0)
n
( i)( i)
i=1
In this case, pre-cruise calibration coefficients would be used and:
islope = 1.0 + (b / n) (preslope - 1.0)
Correcting for Conductivity Drift Based on Salinity Bottles Taken At Sea
For this situation, the pre-cruise calibration coefficients are used to compute conductivity and CTD salinity. Salinity
samples are obtained using water sampler bottles during CTD profiles, and the difference between CTD salinity and
bottle salinity is used to determine the drift in conductivity.
In using this method to correct conductivity, it is important to realize that differences between CTD salinity and
hydrographic bottle salinity are due to errors in conductivity, temperature, and pressure measurements, as well as
errors in obtaining and analyzing bottle salinity values. For typical Sea-Bird sensors that are calibrated regularly,
70 - 90% of the CTD salinity error is due to conductivity calibration drift, 10 - 30% is due to temperature calibration
drift, and 0 - 10% is due to pressure calibration drift. All CTD temperature and pressure errors and bottle errors must
first be corrected before attributing the remaining salinity difference as due to CTD conductivity error and proceeding
with conductivity corrections.
2

Example
Three salinity bottles are taken during a CTD profile; assume for this discussion that shipboard analysis of the
bottle salinities is perfect. The uncorrected CTD data (from SEASAVE) and bottle salinities are:
CTD Raw
Approximate
CTD Raw
CTD Raw
CTD Raw
Bottle
Conductivity
Depth (m)
Pressure (dbar) Temperature (°C) *
Salinity
Salinity
(S/m)
200
202.7
18.3880
4.63421
34.9705
34.9770
1000
1008.8
3.9831
3.25349
34.4634
34.4710
4000
4064.1
1.4524
3.16777
34.6778
34.6850
* Temperatures shown are ITS-90. However, the salinity equation is in terms of ITS-68; you must convert
ITS-90 to ITS-68 (ITS-68 = 1.00024 * ITS-90) before calculating salinity. SEASOFT does this automatically.
The uncorrected salinity differences (CTD raw salinity - bottle salinity) are approximately -0.007 psu. To
determine conductivity drift, first correct the CTD temperature and pressure data. Suppose that the error in
temperature is +0.0015 °C uniformly at all temperatures, and the error in pressure is +0.5 dbar uniformly at all
pressures (drift offsets are obtained by projecting the drift history of both sensors from pre-cruise calibrations).
Enter these offsets in the .con file to calculate the corrected CTD temperature and pressure, and calculate the CTD
salinity using the corrected CTD temperature and pressure. This correction method assumes that the pressure
coefficient for the conductivity cell is correct. The CTD data with corrected temperature (ITS-90) and pressure
are:
Corrected CTD
Corrected CTD
CTD Raw
CTD Salinity
Bottle
Pressure (dbar)
Temperature (°C) Conductivity (S/m) [T,P Corrected]
Salinity
202.2
18.3865
4.63421
34.9719
34.9770
1008.3
3.9816
3.25349
34.4653
34.4710
4063.6
1.4509
3.16777
34.6795
34.6850
The salinity difference (CTD salinity – bottle salinity) of approximately -0.005 psu is now properly categorized as
conductivity error, equivalent to about -0.0005 S/m at 4.0 S/m.
Compute bottle conductivity (conductivity calculated from bottle salinity and CTD temperature and pressure) using
SeacalcW (in SBE Data Processing); enter bottle salinity for salinity, corrected CTD temperature for ITS-90
temperature, and corrected CTD pressure for pressure:
CTD Raw Conductivity (S/m)
Bottle Conductivity (S/m) [CTD - Bottle] Conductivity (S/m)
4.63421
4.63481
-0.00060
3.25349
3.25398
-0.00049
3.16777
3.16822
-0.00045
By plotting conductivity error versus conductivity, it is evident that the drift is primarily a slope change.
If is the CTD conductivity computed with pre-cruise coefficients and is the true bottle conductivity, then:
n
( i)( i)
slope =
i=1
(slope is typically > 1.0)
n
( i)( i)
i=1
Using the above data, the slope correction coefficient for conductivity at this station is:
Slope = [(4.63421 * 4.63481) + (3.25349 * 3.25398) + (3.16777 * 3.16822)] /
[(4.63421 * 4.63421) + (3.25349 * 3.25349) + (3.16777 * 3.16777)] = +1.000138
Following Sea-Bird’s recommendation of assuming no offset error in conductivity, set offset to 0.0.
3

Temperature Sensors
The temperature sensor slope and offset entries in the configuration (.con) file in SEASOFT permit the user to make
corrections for sensor drift between calibrations. The correction formula is:
corrected temperature = slope * (computed temperature) + offset
where :
slope = (true temperature span) / (instrument reading temperature span)
offset = (true temperature - instrument reading temperature) * slope
measured at 0.0 °C
For newly calibrated sensors, use slope = 1.0, offset = 0.0.
Sea-Bird temperature sensors usually drift by changing offset (an error of equal magnitude at all temperatures). In
general, the drift can be toward higher or lower temperature with time; however, for a specific sensor the drift remains
the same sign (direction) for many consecutive years. Many years of experience with thousands of sensors indicates
that the drift is smooth and uniform with time, allowing users to make very accurate drift corrections to field data based
only on pre- and post-cruise laboratory calibrations.
Span errors cause slope errors, as described in the equation for slope above. Sea-Bird temperature sensors rarely exhibit
span errors larger than 0.005 °C over the range -5 to 35 °C, even after years of drift. Temperature calibrations
performed at Sea-Bird since January 1995 have slope errors less than 0.0002 °C in 30 °C. Prior to January 1995, some
calibrations were delivered that include slope errors up to 0.004 °C in 30 °C because of undetected systematic errors in
calibration. A slope error that increases by more than ±0.0002 [°C per °C per year] indicates an unusual aging of
electronic components and is symptomatic of sensor malfunction. Therefore, Sea-Bird recommends that drift
corrections to temperature sensors be made assuming no slope error, unless there is strong evidence to the
contrary or a special need.
Calibration checks at-sea are advisable for consistency checks of the sensor drift rate and for early detection of sensor
malfunction. However, data from reversing thermometers is rarely accurate enough to make calibration corrections that
are better than those possible by shore-based laboratory calibrations. For the SBE 9plus, a proven alternate consistency
check is to use dual SBE 3 temperature sensors on the CTD and to track the difference in drift rates between the two
sensors. In the deep ocean, where temperatures are uniform, the difference in temperature measured by two sensors can
be resolved to better than 0.0002 °C and will change smoothly with time as predicted by the difference in drift rates of
the two sensors.
4

Correcting for Temperature Drift Based on Pre- and Post-Cruise Laboratory Calibrations
Suppose a temperature sensor is calibrated (pre-cruise), then immediately used at-sea, and then returned for postcruise calibration. The pre-and post-cruise calibration data can be used to generate an offset correction for data
obtained between the pre- and post-cruise calibrations.
Calibration coefficients are calculated with the post-cruise calibration. Using the pre-cruise bath data and the post-cruise
calibration coefficients, a mean residual over the calibration temperature range is calculated.
residual = instrument temperature – bath temperature
Sea-Bird calculates and prints the value for the residual on the temperature calibration sheet.
To correct temperature data taken between pre- and post-cruise calibrations:
Offset = b * (residual / n)
where
b = number of days between pre-cruise calibration and the cast to be corrected
n = number of days between pre- and post-cruise calibrations
residual = residual from calibration sheet as described above
In the .con file, use the pre-cruise calibration coefficients and use the negative of the offset for the value of offset
(offset is added, so to remove negative drift a positive number is entered in the .con file).
Note: The CTD configuration (.con) file is edited using the Configure menu (in SEASAVE or SBE Data Processing in
our SEASOFT-Win32 suite of programs) or the Configure Inputs menu in SEASAVE V7.
Example
Instrument was calibrated (pre-cruise), used at sea for 4 months, and returned for post-cruise calibration.
Using pre-cruise bath data and post-cruise coefficients, the calibration sheet shows a mean residual of
-0.2 millidegrees C (-0.0002 °C).
For preliminary work at sea, use the pre-cruise calibration coefficients and slope = 1.0, offset = 0.0.
After the cruise, correct temperature data obtained during the cruise for drift using properly scaled values of
correction coefficients:
For data from the end of the first month (30 days) at sea:
Offset = b * (residual / n) = 30 * (0.0002 / 120) = - 0.00005;
Convert data using pre-cruise coefficients and +0.00005 as the offset in the .con file.
(Notice the change in sign for the offset entry in the .con file)
For data from the end of the second month (60 days) at sea:
Offset = b * (residual / n) = 60 * (0.0002 / 120) = - 0.0001;
Convert data using pre-cruise coefficients and +0.0001 as the offset in the .con file.
For data from the end of the third month (90 days) at sea:
Offset = b * (residual / n) = 90 * (0.0002 / 120) = - 0.00015;
Convert data using pre-cruise coefficients and +0.00015 as the offset in the .con file.
For data from the end of the 4-month cruise:
Offset = - 0.0002;
Convert data using pre-cruise coefficients and +0.0002 as the offset in the .con file, or using post-cruise
coefficients and 0 as the offset in the .con file.
5

Sea-Bird Electronics, Inc.
1808 136th Place NE
Bellevue, WA 98005
USA
Phone: (425) 643-9866
Fax: (425) 643-9954
E-mail: seabird@seabird.com
Web: www.seabird.com
APPLICATION NOTE NO. 34
Revised January 2005
Instructions for Use of Conductivity Cell Filling and Storage Device PN 50087 and 50087.1
This application note provides instructions for use
of PN 50087 / 50087.1 syringe and tubing assembly
in rinsing, cleaning, and storing conductivity
sensors. The tubing assembly consists of a length of
6.35 mm (1/4 inch) I.D. tube connected by a plastic
reducing union to a short piece of 11.1 mm
(7/16 inch) I.D. tube. Refer to Application Note 2D:
Instructions for Care and Cleaning of Conductivity
Cells for information on water and solutions
recommended for use.
SBE 9plus, 19plus, 25, and 49 are shipped with
PN 50087.
SBE 16plus and 16plus-IM are shipped with
PN 50087.1, which includes the parts in 50087,
plus hose barbs to replace the anti-foulant cap
on the instrument. The hose barbs allow for
connection of the tubing for cleaning and
storing, as described below.
Procedure for Use
1. To fill the conductivity cell, draw about
40-60 cc of solution into the syringe.
2. Connect the plastic tubing to the TC duct intake
on the temperature sensor [Figure 1]
(or to the open end of the conductivity cell on
systems without the TC duct [Figure 2]),
and inject solution into the cell and
pump plumbing.
CTDs with a TC duct or hose barb fitting remove the plastic reducing union and
connect the smaller diameter tubing directly
to the TC duct / fitting.
CTDs without a TC duct or hose barb
fitting (older instruments) - leave the
reducing union and large diameter tubing
attached and carefully connect the tubing
directly to the end of the glass conductivity
cell [Figure 2].
3. (If applicable) Loop the rubber band around a
bar on the CTD cage and back over the top of
the syringe to secure the apparatus for storage.
REMOVE THE SYRINGE AND TUBING ASSEMBLY BEFORE DEPLOYMENT!

Sea-Bird Electronics, Inc.
1808 136th Place NE
Bellevue, WA 98005
USA
Phone: (425) 643-9866
Fax: (425) 643-9954
E-mail: seabird@seabird.com
Web: www.seabird.com
APPLICATION NOTE NO. 40
Revised May 2005
SBE 5T PUMP SPEED ADJUSTMENT INSTRUCTIONS
Equipment: DC power supply
Frequency counter
Drawings:
31441B (schematic)
41250A (assembly)
The pump housing must be disassembled to adjust the pump speed. Referencing above drawings:
1. Remove the white plastic end cap retainer ring located at the connector end of the pump by twisting in a
counter-clockwise motion.
2. Install a 2-pin dummy plug with locking sleeve over the bulkhead connector to provide a good grip on
the pump connector and protect the connector pins. Rotate the connector back and forth while carefully
pulling the end cap away from the housing. Pull the end cap (piston o-ring seal) out of the housing. The
motor and electronics assembly are attached to the end cap and will come out as a unit.
3. Connect the positive lead of your frequency counter to the yellow test post (T1) (drawing 41250A).
Connect the frequency counter ground (negative) to the power supply ground (negative).
4. Supply power:
Low voltage pump (pump with LV in the serial number) - Supply 6 volts DC power to the
bulkhead connector (large pin is common, small pin is positive) or directly to the PCB
(P8 is positive, P19 or P18 is common, drawing 41250A).
Normal voltage pump - Supply 12 volts to the bulkhead connector (large pin is common, small pin
is positive) or directly to the PCB (P8 is positive, P19 or P18 is common, drawing 41250A).
5. A 2K ohm potentiometer (R11, drawing 41250A) is located on the back side of the board. Adjust the
potentiometer to obtain the frequency corresponding to the desired speed (Frequency * 30 = rpm):
Pittman 18.2 motor (P/N 3711B113-R1) - Set jumper position P15 to P17 (1300 rpm) and P12
to P13 (1300 rpm), and adjust the speed as desired, up to the nominal maximum of 2000 rpm.
Pittman 7.4 motor (P/N 3711B112-R1) - Set jumper position P15 to P16 (3000 rpm) and P14
to P13 (3000 rpm), and adjust the speed as desired, up to the nominal maximum of 4500 rpm.
To adjust speed below approximately 2200 rpm, set jumper position P15 to P17 (1300 rpm) and
P12 to P13 (1300 rpm), and adjust speed using the potentiometer.
Pittman 3.55 motor (P/N 3711B112-R2) - Set jumper position P15 to P16 (3000 rpm) and P14
to P13 (3000 rpm), and adjust the speed as desired, up to the nominal maximum of 4500 rpm.
To adjust speed below approximately 2200 rpm, set jumper position P15 to P17 (1300 rpm) and
P12 to P13 (1300 rpm), and adjust speed using the potentiometer.
6. Disconnect the frequency counter and the power supply. Make sure the O-ring and mating surfaces
are clean. Lightly lubricate the o-ring before inserting the connector end cap into the housing. Replace
the pump end cap retainer.
1
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             
                 

                

              





              



                   




                
              
               


Sea-Bird Electronics, Inc.
1808 136th Place NE
Bellevue, WA 98005
USA
Phone: (425) 643-9866
Fax: (425) 643-9954
E-mail: seabird@seabird.com
Web: www.seabird.com
APPLICATION NOTE NO. 57
Revised May 2003
I/O Connector Care and Installation
This Application Note describes the proper care and installation of standard I/O connectors for Sea-Bird
CTD instruments. Once properly installed, the connections require minimal care. Unless access to the bulkhead is
required, the connections can be left in place indefinitely.
The Application Note is divided into three sections:
Connector Cleaning and Installation
Locking Sleeve Installation
Cold Weather Tips
Connector Cleaning and Installation
1.
Carefully clean the bulkhead connector and the inside of the mating inline (cable end) connector with a
Kimwipe. Remove all grease, hair, dirt, and other contamination.
Clean bulkhead connector
2.
Clean inside of connector
Inspect the connectors:
A. Inspect the pins on the bulkhead connector for signs of corrosion. The pins should be bright and shiny, with no
discoloration. If the pins are discolored or corroded, clean with alcohol and a Q-tip.
B. Inspect the bulkhead connector for chips, cracks, or other flaws that may compromise the seal.
C. Inspect the inline connector for cuts, nicks, breaks, or other problems that may compromise the seal.
Replace severely corroded or otherwise damaged connectors - contact SBE for instructions or a Return
Authorization Number (RMA number).
Corroded pins on bulkhead connectors Connector on right has a missing pin

3.
Using a tube of 100% silicone grease (Dow DC-4 or
equivalent), squeeze approximately half the size of a
pea onto the end of your finger.
CAUTION:
Do not use WD-40 or other petroleum-based
lubricants, as they will damage the connectors.
4.
7.
Apply a light, even coating of grease to the molded
ridge around the base of the bulkhead connector.
The ridge looks like an o-ring molded into the
bulkhead connector base and fits into the groove of
the mating inline connector.
After the cable is mated, run your fingers along the
inline connector toward the bulkhead, milking any
trapped air out of the connector. You should hear
the air being ejected.
CAUTION:
Failure to eject the trapped air will result in the
connector leaking.
5.
Mate the inline connector to the bulkhead,
being careful to align the pins with the sockets.
Do not twist the inline connector on the
bulkhead connector. Twisting can lead to bent
pins, which will soon break.
6.
Push the connector all the way onto the
bulkhead. There may be an audible pop,
which is good. With some newer cables,
or in cold weather, there may not be an
initial audible pop.

Locking Sleeve Installation
After the connectors are mated, install the locking sleeve. The locking sleeve secures the inline connector to the
bulkhead connector and prevents the cable from being inadvertently removed.
Important points regarding locking sleeves:
Tighten the locking sleeve by hand. Do not use a wrench or pliers to tighten the locking sleeve.
Overtightening will gall the threads, which can bind the locking sleeve to the bulkhead connector. Attempting
to remove a tightly bound locking sleeve may instead result in the bulkhead connector actually unthreading
from the end cap. A loose bulkhead connector will lead to a flooded instrument. Pay particular attention
when removing a locking sleeve to ensure the bulkhead connector is not loosened.
It is a common misconception that the locking sleeve provides watertight integrity. It does not, and
continued re-tightening of the locking sleeve will not fix a leaking connector.
As part of routine maintenance at the end of every cruise, remove the locking sleeve, slide it up the cable, and
rinse the connection (still mated) with fresh water. This will prevent premature cable failure.
Locking Sleeve
Cold Weather Tips
In cold weather, the connector may be hard to install and remove.
Removing a frozen inline connector:
1.
Wrap the connector with a washrag or other cloth.
2.
Pour hot water on the cloth and let the connector sit for a minute or two. The connector should thaw and become
flexible enough to be removed.
Installing an inline connector:
When possible, mate connectors in warm environments before the cruise and leave them connected.
If not, warm the connector sufficiently so it is flexible. A flexible connector will install properly.
By following these procedures, you will have many years of reliable service from your cables!



















 
 
 

 





















 



 




Sea-Bird Electronics, Inc.
1808 136th Place NE
Bellevue, WA 98005
USA
Phone: (425) 643-9866
Fax: (425) 643-9954
E-mail: seabird@seabird.com
Web: www.seabird.com
APPLICATION NOTE NO. 68
Revised November
2006
Using USB Ports to Communicate with Sea-Bird Instruments
Most Sea-Bird instruments use the RS-232 protocol for transmitting setup commands to the
instrument and receiving data from the instrument. However, many newer PCs and laptop
computers have USB port(s) instead of RS-232 serial port(s).
USB serial adapters are available commercially. These adapters plug into the USB port, and allow
one or more serial devices to be connected through the adapter. Sea-Bird tested USB serial adapters
from three manufacturers on desktop computers at Sea-Bird, and verified compatibility with our
instruments. These manufacturers and the tested adapters are:
IOGEAR (www.iogear.com) –
USB 1.1 to Serial Converter Cable (model # GUC232A).
Note: This adapter can also be purchased from Sea-Bird, as Sea-Bird part # 20163.
Keyspan (www.keyspan.com) USB 4-Port Serial Adapter (part # USA-49WLC, replacing part # USA-49W)
Edgeport (www.ionetworks.com) Standard Serial Converter Edgeport/2 (part # 301-1000-02)
Other USB adapters from these manufacturers, and adapters from other manufacturers, may also be
compatible with Sea-Bird instruments.
We have one report from a customer that he could not communicate with his instrument using a
notebook computer and the Keyspan adapter listed above. He was able to successfully communicate
with the instrument using an XH8290 DSE Serial USB Adapter (www.dse.co.nz).
We recommend testing any adapters, including those listed above, with the instrument and the
computer you will use it with before deployment, to verify that there is no problem.
1

Sea-Bird Electronics, Inc.
1808 136th Place NE
Bellevue, WA 98005
USA
Phone: (425) 643-9866
Fax: (425) 643-9954
E-mail: seabird@seabird.com
Web: www.seabird.com
APPLICATION NOTE NO. 69
July 2002
Conversion of Pressure to Depth
Sea-Bird’s SEASOFT software can calculate and output depth, if the instrument data includes
pressure. Additionally, some Sea-Bird instruments (such as the SBE 37-SI or SBE 50) can be set up
by the user to internally calculate depth, and to output depth along with the measured parameters.
Sea-Bird uses the following algorithms for calculating depth:
Fresh Water Applications
Because most fresh water applications are shallow, and high precision in depth not too critical,
Sea-Bird software uses a very simple approximation to calculate depth:
depth (meters) = pressure (decibars) * 1.019716
Seawater Applications
Sea-Bird uses the formula in UNESCO Technical Papers in Marine Science No. 44. This is an
empirical formula that takes compressibility (that is, density) into account. An ocean water column
at 0 °C (t = 0) and 35 PSU (s = 35) is assumed.
The gravity variation with latitude and pressure is computed as:
g (m/sec2) = 9.780318 * [ 1.0 + ( 5.2788x10 -3 + 2.36x10 -5 * x) * x ] + 1.092x10 -6 * p
where
x = [sin (latitude / 57.29578) ] 2
p = pressure (decibars)
Then, depth is calculated from pressure:
depth (meters) = [(((-1.82x10 -15 * p + 2.279x10 -10 ) * p - 2.2512x10 -5 ) * p + 9.72659) * p] / g
where
p = pressure (decibars)
g = gravity (m/sec2)
1

Sea-Bird Electronics, Inc.
1808 136th Place NE
Bellevue, WA 98005
USA
Phone: (425) 643-9866
Fax: (425) 643-9954
E-mail: seabird@seabird.com
Web: www.seabird.com
APPLICATION NOTE NO. 71
Revised July 2005
Desiccant Use and Regeneration (drying)
This application note applies to all Sea-Bird instruments intended for underwater use. The application note covers:
When to replace desiccant
Storage and handling of desiccant
Regeneration (drying) of desiccant
Material Safety Data Sheet (MSDS) for desiccant
When to Replace Desiccant Bags
Before delivery of the instrument, a desiccant package is placed in the housing, and the electronics chamber is filled with dry
Argon. These measures help prevent condensation. To ensure proper functioning:
1. Install a new desiccant bag each time you open the housing and expose the electronics.
2. If possible, dry gas backfill each time you open the housing and expose the electronics. If you cannot, wait at least
24 hours before redeploying, to allow the desiccant to remove any moisture from the chamber.
What do we mean by expose the electronics?
For most battery-powered Sea-Bird instruments (such as SBE 16, 16plus, 16plus-IM, 17plus, 19, 19plus, 25, 26,
26plus, 37-SM, 37-SMP, 37-IM, 37-IMP, 44, 53; Auto Fire Module [AFM]), there is a bulkhead between the battery
and electronics compartments. Battery replacement does not affect desiccation of the electronics, as the batteries are
removed without removing the electronics and no significant gas exchange is possible through the bulkhead. Therefore,
opening the battery compartment to replace the batteries does not expose the electronics; you do not need to install a
new desiccant bag in the electronics compartment each time you open the battery compartment. For these instruments,
install a new desiccant bag if you open the electronics compartment to access the printed circuit boards.
For the SBE 39, 39-IM, and 48, the electronics must be removed or exposed to access the battery. Therefore, install a
new desiccant bag each time you open the housing to replace a battery.
Storage and Handling
Testing by Süd-Chemie (desiccant’s manufacturer)
at 60% relative humidity and 30 °C shows that
approximately 25% of the desiccant’s adsorbing
capacity is used up after only 1 hour of exposure to
a constantly replenished supply of moisture in the
air. In other words, if you take a bag out of a
container and leave it out on a workbench for
1 hour, one-fourth of its capacity is gone before
you ever install it in the instrument. Therefore:
Keep desiccant bags in a tightly sealed,
impermeable container until you are ready to
use them. Open the container, remove a bag,
and quickly close the container again.
Once you remove the bag(s) from the sealed
container, rapidly install the bag(s) in the
instrument housing and close the housing.
Do not use the desiccant bag(s) if exposed to
air for more than a total of 30 minutes.
1

Regeneration (drying) of Desiccant
Replacement desiccant bags are available from Sea-Bird:
PN 60039 is a metal can containing 25 1-gram desiccant bags and 1 humidity indicator card. The 1-gram bags are
used in our smaller diameter housings, such as the SBE 3 (plus, F, and S), 4 (M and C), 5T, 37 (-SI, -SIP, -SM,
-SMP, -IM, and –IMP), 38, 39, 39-IM, 43, 44, 45, 48, 49, and 50.
PN 31180 is a 1/3-ounce desiccant bag, used in our SBE 16plus, 16plus-IM, 19plus, 21, and 52-MP.
PN 30051 is a 1-ounce desiccant bag. The 1-ounce bags are used in our larger diameter housings, such as the
SBE 9plus, 16, 17plus, 19, 25, 26, 26plus, 32, 53 BPR, AFM, and PDIM.
However, if you run out of bags, you can regenerate your existing bags using the following procedure provided by the
manufacturer (Süd-Chemie Performance Packaging, a Division of United Catalysts, Inc.):
MIL-D-3464 Desiccant Regeneration Procedure
Regeneration of the United Desiccants’ Tyvek Desi Pak® or Sorb-It® bags or United Desiccants’
X-Crepe Desi Pak® or Sorb-It® bags can be accomplished by the following method:
1. Arrange the bags on a wire tray in a single layer to allow for adequate air flow around the bags
during the drying process. The oven’s inside temperature should be room or ambient temperature
(25 – 29.4 °C [77 – 85 °F] ). A convection, circulating, forced-air type oven is recommended for
this regeneration process. Seal failures may occur if any other type of heating unit or appliance
is used.
2. When placed in forced air, circulating air, or convection oven, allow a minimum of 3.8 to 5.1 cm
(1.5 to 2.0 inches) of air space between the top of the bags and the next metal tray above the bags.
If placed in a radiating exposed infrared-element type oven, shield the bags from direct exposure to the
heating element, giving the closest bags a minimum of 40.6 cm (16 inches) clearance from the heat
shield. Excessive surface film temperature due to infrared radiation will cause the Tyvek material to
melt and/or the seals to fail. Seal failure may also occur if the temperature is allowed to increase
rapidly. This is due to the fact that the water vapor is not given sufficient time to diffuse through the
Tyvek material, thus creating internal pressure within the bag, resulting in a seal rupture. Temperature
should not increase faster than 0.14 to 0.28 °C (0.25 to 0.50 °F) per minute.
3. Set the temperature of the oven to 118.3 °C (245 °F), and allow the bags of desiccant to reach
equilibrium temperature. WARNING: Tyvek has a melt temperature of 121.1 – 126.7 °C
(250 – 260 °F) (Non MIL-D-3464E activation or reactivation of both silica gel and Bentonite clay can
be achieved at temperatures of 104.4 °C [220 °F]).
4. Desiccant bags should be allowed to remain in the oven at the assigned temperature for 24 hours.
At the end of the time period, the bags should be immediately removed and placed in a desiccator jar or
dry (0% relative humidity) airtight container for cooling. If this procedure is not followed precisely,
any water vapor driven off during reactivation may be re-adsorbed during cooling
and/or handling.
5. After the bags of desiccant have been allowed to cool in an airtight desiccator, they may be removed
and placed in either an appropriate type polyliner tightly sealed to prevent moisture adsorption, or a
container that prevents moisture from coming into contact with the regenerated desiccant.
NOTE: Use only a metal or glass container with a tight fitting metal or glass lid to store the regenerated desiccant. Keep
the container lid closed tightly to preserve adsorption properties of the desiccant.
2

Sud-Chemie Performance
Packaging
101 Christine Dr.
Belen, New Mexico 87002
Phone: (505) 864-6691
Fax: (505) 864-9296
ISO 9002 CERTIFIED
MATERIAL SAFETY DATA SHEET – August 13, 2002
SORB-IT®
Packaged Desiccant
SECTION I -- PRODUCT IDENTIFICATION
Trade Name and Synonyms:
Silica Gel, Synthetic Amorphous Silica,
Silicon, Dioxide
Synthetic Amorphous Silica
SiO2.x H2O
Chemical Family:
Formula:
SECTION II -- HAZARDOUS INGREDIENTS
COMPONENT
Amorphous
Silica
Components in the Solid Mixture
CAS No
%
ACGIH/TLV (PPM)
OSHA-(PEL)
63231-67-4
>99
PEL - 20 (RESPIRABLE), LIMIT – NONE,
TLV – 5
HAZARD IRRITANT
Synthetic amorphous silica is not to be confused with crystalline silica such as quartz,
cristobalite or tridymite or with diatomaceous earth or other naturally occurring forms of
amorphous silica that frequently contain crystalline forms.
This product is in granular form and packed in bags for use as a desiccant. Therefore, no
exposure to the product is anticipated under normal use of this product. Avoid inhaling
desiccant dust.
SECTION III -- PHYSICAL DATA
Appearance and Odor:
Melting Point:
Solubility in Water:
Bulk Density:
Percent Volatile by Weight @ 1750 Deg F:
White granules; odorless.
>1600 Deg C; >2900 Deg F
Insoluble.
>40 lbs./cu. ft.
<10%.
3

Sud-Chemie Performance
Packaging
101 Christine Dr.
Belen, New Mexico 87002
Phone: (505) 864-6691
Fax: (505) 864-9296
ISO 9002 CERTIFIED
MATERIAL SAFETY DATA SHEET – August 13, 2002
SORB-IT®
Packaged Desiccant
SECTION IV -- FIRE EXPLOSION DATA
Fire and Explosion Hazard - Negligible fire and explosion hazard when exposed to heat
or flame by reaction with incompatible substances.
Flash Point - Nonflammable.
Firefighting Media - Dry chemical, water spray, or foam. For larger fires, use water spray
fog or foam.
Firefighting - Nonflammable solids, liquids, or gases: Cool containers that are exposed
to flames with water from the side until well after fire is out. For massive fire in enclosed
area, use unmanned hose holder or monitor nozzles; if this is impossible, withdraw from
area and let fire burn. Withdraw immediately in case of rising sound from venting safety
device or any discoloration of the tank due to fire.
SECTION V -- HEALTH HAZARD DATA
Health hazards may arise from inhalation, ingestion, and/or contact with the skin and/or
eyes. Ingestion may result in damage to throat and esophagus and/or gastrointestinal
disorders. Inhalation may cause burning to the upper respiratory tract and/or temporary or
permanent lung damage. Prolonged or repeated contact with the skin, in absence of
proper hygiene, may cause dryness, irritation, and/or dermatitis. Contact with eye tissue
may result in irritation, burns, or conjunctivitis.
First Aid (Inhalation) - Remove to fresh air immediately. If breathing has stopped, give
artificial respiration. Keep affected person warm and at rest. Get medical attention
immediately.
First Aid (Ingestion) - If large amounts have been ingested, give emetics to cause
vomiting. Stomach siphon may be applied as well. Milk and fatty acids should be
avoided. Get medical attention immediately.
First Aid (Eyes) - Wash eyes immediately and carefully for 30 minutes with running
water, lifting upper and lower eyelids occasionally. Get prompt medical attention.
First Aid (Skin) - Wash with soap and water.
4

Sud-Chemie Performance
Packaging
101 Christine Dr.
Belen, New Mexico 87002
Phone: (505) 864-6691
Fax: (505) 864-9296
ISO 9002 CERTIFIED
MATERIAL SAFETY DATA SHEET – August 13, 2002
SORB-IT®
Packaged Desiccant
NOTE TO PHYSICIAN: This product is a desiccant and generates heat as it adsorbs
water. The used product can contain material of hazardous nature. Identify that material
and treat accordingly.
SECTION VI -- REACTIVITY DATA
Reactivity - Silica gel is stable under normal temperatures and pressures in sealed
containers. Moisture can cause a rise in temperature which may result in a burn.
SECTION VII --SPILL OR LEAK PROCEDURES
Notify safety personnel of spills or leaks. Clean-up personnel need protection against
inhalation of dusts or fumes. Eye protection is required. Vacuuming and/or wet methods
of cleanup are preferred. Place in appropriate containers for disposal, keeping airborne
particulates at a minimum.
SECTION VIII -- SPECIAL PROTECTION INFORMATION
Respiratory Protection - Provide a NIOSH/MSHA jointly approved respirator in the
absence of proper environmental control. Contact your safety equipment supplier for
proper mask type.
Ventilation - Provide general and/or local exhaust ventilation to keep exposures below
the TLV. Ventilation used must be designed to prevent spots of dust accumulation or
recycling of dusts.
Protective Clothing - Wear protective clothing, including long sleeves and gloves, to
prevent repeated or prolonged skin contact.
Eye Protection - Chemical splash goggles designed in compliance with OSHA
regulations are recommended. Consult your safety equipment supplier.
SECTION IX -- SPECIAL PRECAUTIONS
Avoid breathing dust and prolonged contact with skin. Silica gel dust causes eye irritation
and breathing dust may be harmful.
5

Sud-Chemie Performance
Packaging
101 Christine Dr.
Belen, New Mexico 87002
Phone: (505) 864-6691
Fax: (505) 864-9296
ISO 9002 CERTIFIED
MATERIAL SAFETY DATA SHEET – August 13, 2002
SORB-IT®
Packaged Desiccant
* No Information Available
HMIS (Hazardous Materials Identification System) for this product is as
follows:
Health Hazard
Flammability
Reactivity
Personal Protection
0
0
0
HMIS assigns choice of personal protective equipment to the
customer, as the raw material supplier is unfamiliar with the
condition of use.
The information contained herein is based upon data considered true and accurate. However, United Desiccants makes no warranties
expressed or implied, as to the accuracy or adequacy of the information contained herein or the results to be obtained from the use
thereof. This information is offered solely for the user's consideration, investigation and verification. Since the use and conditions of
use of this information and the material described herein are not within the control of United Desiccants, United Desiccants assumes no
responsibility for injury to the user or third persons. The material described herein is sold only pursuant to United Desiccants' Terms
and Conditions of Sale, including those limiting warranties and remedies contained therein. It is the responsibility of the user to
determine whether any use of the data and information is in accordance with applicable federal, state or local laws and regulations.
6

Sea-Bird Electronics, Inc.
1808 136th Place NE
Bellevue, WA 98005
USA
Phone: (425) 643-9866
Fax: (425) 643-9954
E-mail: seabird@seabird.com
Web: www.seabird.com
APPLICATION NOTE NO. 73
Revised July 2005
Using Instruments with Pressure Sensors at Elevations Above Sea Level
This application note covers use of a Sea-Bird instrument that includes a pressure sensor at elevations above sea level,
such as in a mountain lake or stream.
Background
Sea-Bird pressure sensors are absolute sensors, so their raw output includes the effect of atmospheric pressure. As
shown on the Calibration Sheet that accompanies the instrument, our calibration (and resulting calibration coefficients)
is in terms of psia. However, when outputting pressure in engineering units, most of our instruments output pressure
relative to the ocean surface (i.e., at the surface the output pressure is 0 decibars). Sea-Bird uses the following equation
in our instruments and/or software to convert psia to decibars:
Pressure (db) = [pressure (psia) – 14.7] * 0.689476
where 14.7 psia is the assumed atmospheric pressure (based on atmospheric pressure at sea level).
This conversion is based on the assumption that the instrument is being used in the ocean; the surface of the ocean
water is by definition at sea level. However, if the instrument is used in a mountain lake or stream, the assumption of
sea level atmospheric pressure (14.7 psia) in the instrument and/or software can lead to incorrect results. Procedures are
provided below for measuring the pressure offset from the assumed sea level atmospheric pressure, and entering the
offset in the instrument and/or software to make the appropriate correction.
Perform the correction procedure at the elevation at which the instrument will be deployed. Allow the
instrument to equilibrate in a reasonably constant temperature environment for at least 5 hours before starting.
Pressure sensors exhibit a transient change in their output in response to changes in their environmental
temperature. Sea-Bird instruments are constructed to minimize this by thermally decoupling the sensor from the
body of the instrument. However, there is still some residual effect; allowing the instrument to equilibrate before
starting will provide the most accurate calibration correction.
Inclusion of calibration coefficients in the instrument itself or in a file used by our software to interpret raw data varies,
depending on the instrument. Commands used to program the instrument vary as well. Therefore, there are variations in
the correction procedure, depending on the instrument. These instruments are addressed below:
SBE 9plus CTD and SBE 25 SEALOGGER CTD
SBE 16plus (RS-232 version) SEACAT C-T (pressure optional) Recorder, SBE 19plus SEACAT Profiler CTD,
and SBE 49 FastCAT CTD Sensor
SBE 16plus (RS-485 version) SEACAT C-T (pressure optional) Recorder and
SBE 16plus-IM SEACAT C-T (pressure optional) Recorder
SBE 37 MicroCAT (all models – IM, IMP, SI, SIP, SM, SMP)
SBE 50 Digital Oceanographic Pressure Sensor
SBE 52-MP Moored Profiler CTD and DO Sensor
SBE 39-IM Temperature (pressure optional) Recorder
SBE 39 Temperature (pressure optional) Recorder
SBE 26plus SEAGAUGE Wave and Tide Recorder and SBE 53 BPR Bottom Pressure Recorder
1

SBE 9plus and 25
Sea-Bird software (SEASAVE or SBE Data Processing) uses calibration coefficients programmed in a configuration
(.con) file to convert raw data from these instruments to engineering units.
Follow this procedure to correct the pressure:
1. With the instrument in the air, place it in the orientation it will have when deployed.
2. In SEASAVE, in the .con file, set the pressure offset to 0.0.
3. Acquire data in SEASAVE, and display the pressure sensor output in decibars.
4. Calculate offset = (0 – instrument reading).
5. Enter the calculated offset in the .con file.
Offset Correction Example:
Pressure displayed at elevation is -1.655 db.
Enter offset in .con file.
Offset = 0 – (-1.655) = + 1.655 db
SBE 16plus (RS-232 version), 19plus, and 49
Sea-Bird software (SEASAVE or SBE Data Processing) uses calibration coefficients programmed in a configuration
(.con) file to convert raw data from these instruments to engineering units. These instruments are also able to directly
output data that is already converted to engineering units (pressure in decibars), using calibration coefficients that are
programmed into the instrument.
Follow this procedure to correct the pressure:
1. With the instrument in the air, place it in the orientation it will have when deployed.
2. In SEASAVE, in the .con file, set the pressure offset to 0.0.
3. Acquire data in SEASAVE, and display the pressure sensor output in decibars.
4. Calculate offset = (0 – instrument reading).
5. Enter the calculated offset in the .con file.
6. Also enter the calculated offset in the instrument (use the POFFSET= command in SEATERM).
Offset Correction Example:
Pressure displayed at elevation is -1.655 db.
Enter offset in .con file and in instrument.
Offset = 0 – (-1.655) = + 1.655 db
SBE 16plus (RS-485 version) and 16plus-IM
Sea-Bird software (SEASAVE or SBE Data Processing) uses calibration coefficients programmed in a configuration
(.con) file to convert raw data from these instruments to engineering units. These instruments are also able to directly
output data that is already converted to engineering units (pressure in decibars), using calibration coefficients that are
programmed into the instrument.
Follow this procedure to correct the pressure:
1. With the instrument in the air, place it in the orientation it will have when deployed.
2. In SEATERM, set the pressure offset to 0.0 (#iiPOFFSET=0) and set the output format to converted data in
decimal form (#iiOUTPUTFORMAT=3).
3. Acquire data using the #iiTP command.
4. Calculate offset = (0 – instrument reading).
5. Enter the calculated offset in the instrument (use #iiPOFFSET= in SEATERM).
6. Also enter the calculated offset in the .con file, using SBE Data Processing.
Offset Correction Example:
Pressure displayed at elevation is -1.655 db.
Enter offset in .con file and in instrument.
Offset = 0 – (-1.655) = + 1.655 db
2

SBE 37 (all models)
The SBE 37 is able to directly output data that is already converted to engineering units (pressure in decibars), using
calibration coefficients that are programmed into the instrument. The SBE 37 does not use a .con file.
Follow this procedure to correct the pressure:
1. With the SBE 37 in the air, place it in the orientation it will have when deployed.
2. In SEATERM, set the pressure offset to 0.0 and pressure sensor output to decibars. *
3. Acquire data. *
4. Calculate offset = (0 – instrument reading).
5. Enter the calculated offset in the SBE 37 in SEATERM. *
Offset Correction Example:
Pressure displayed at elevation is -1.655 db.
Enter offset in the SBE 37.
Offset = 0 – (-1.655) = + 1.655 db
* NOTE: Commands for setting pressure offset, setting output format, and acquiring data vary:
Pressure Offset
Output Format
Command to
Instrument
Command
Command
Acquire Data
SBE 37-IM and 37-IMP, and
#iiFORMAT=1 or
#iiTP (measures and
RS-485 version of
#iiPOFFSET=
outputs pressure 30 times)
#iiFORMAT=2
SBE 37-SM, 37-SMP, 37-SI, and 37-SIP
RS-232 version of
FORMAT=1 or
TP (measures and outputs
POFFSET=
SBE 37-SM, 37-SMP, 37-SI, and 37-SIP
pressure 100 times)
FORMAT=2
SBE 50
The SBE 50 is able to directly output data that is already converted to engineering units (psia, decibars, or depth in feet
or meters), using calibration coefficients that are programmed into the instrument. The SBE 50 does not use a .con file.
Follow this procedure to correct the pressure:
1. With the SBE 50 in the air, place it in the orientation it will have when deployed.
2. In SEATERM, set the pressure offset to 0.0 (POFFSET=0) and set the output format to the desired format
(OUTPUTFORMAT=).
3. Acquire data using the TS command a number of times.
4. Calculate offset = (0 – instrument reading).
5. Enter the calculated offset in the SBE 50 (use POFFSET= in SEATERM). The offset must be entered in units
consistent with OUTPUTFORMAT=. For example, if the output format is decibars (OUTPUTFORMAT=2),
enter the offset in decibars.
Offset Correction Example:
Pressure displayed at elevation with OUTPUTFORMAT=2 (db) is -1.655 db. Offset = 0 – (-1.655) = + 1.655 db
Enter offset in the SBE 50.
3

SBE 52-MP
The SBE 52-MP is able to directly output data that is already converted to engineering units (pressure in decibars),
using calibration coefficients that are programmed into the instrument. The SBE 52-MP does not use a .con file.
Follow this procedure to correct the pressure:
1. With the SBE 52-MP in the air, place it in the orientation it will have when deployed.
2. In SEATERM, set the pressure offset to 0.0 (POFFSET=0).
3. Acquire data using the TP command.
4. Calculate offset = (0 – instrument reading).
5. Enter the calculated offset in the SBE 52-MP (use POFFSET= in SEATERM).
Offset Correction Example:
Pressure displayed at elevation is -1.655 db. Offset = 0 – (-1.655) = + 1.655 db
Enter offset in the SBE 52-MP.
SBE 39-IM
The SBE 39-IM directly outputs data that is already converted to engineering units (pressure in decibars), using
calibration coefficients that are programmed into the SBE 39-IM. The SBE 39-IM does not use a .con file.
Follow this procedure to correct the pressure:
1. With the SBE 39-IM in the air, place it in the orientation it will have when deployed.
2. In SEATERM, set the pressure offset to 0.0 (#iiPOFFSET=0).
3. Acquire data using the #iiTP command.
4. Calculate offset = (0 – instrument reading).
5. Enter the calculated offset in the SBE 39-IM (use #iiPOFFSET= in SEATERM)
Offset Correction Example:
Pressure displayed at elevation is -1.655 db.
Enter offset in the SBE 39-IM.
Offset = 0 – (-1.655) = + 1.655 db
4

SBE 39
The SBE 39 directly outputs data that is already converted to engineering units (pressure in decibars), using calibration
coefficients that are programmed into the SBE 39. The SBE 39 does not use a .con file. The SBE 39 is a special case,
because its programmed calibration coefficients do not currently include a pressure offset term. The lack of a pressure
offset term creates two difficulties when deploying at elevations above sea level:
After the data is recorded and uploaded, you must perform post-processing to adjust for the pressure offset.
Sea-Bird software cannot currently perform this adjustment for the SBE 39.
Without adjusting the instrument range, internal calculation limitations prevent the SBE 39 from providing accurate
data at high elevations. Specifically, if (0.1 * sensor range) < (decrease in atmospheric pressure from sea level to elevation),
an error condition in the SBE 39’s internal calculations occurs. The table below tabulates the atmospheric pressure and
approximate elevation at which this calculation limitation occurs for different pressure sensor ranges.
Range
(m or db) *
Range (psi) =
Range (db) / 0.689476
0.1 * Range (psi)
20
100
350
1000
2000
3500
7000
29
145
507
1450
2900
5076
10152
2.9
14.5
50.7
145
290
507
1015
Atmospheric Pressure (psi) at
elevation at which error occurs =
[14.7 – 0.1 * Range (psi)]
11.8
0.2
-
Approximate
Corresponding Elevation
(m)
1570
7885
-
* Notes:
Although decibars and meters are not strictly equal, this approximation is close enough for this Application Note.
See Application Note 69 for conversion of pressure (db) to depth (m) for fresh or salt water applications.
Equations used in conversions As shown on page 1: pressure (db) = [pressure (psia) – 14.7] * 0.689476;
Rearranging: pressure (psia) = [Pressure (db) / 0.689476] + 14.7
Measuring relative to atmospheric:
pressure (psi; relative to atmospheric pressure) = Pressure (db) / 0.689476
From the table, it is apparent that the only practical limitation occurs with a 20 meter pressure sensor. To use the SBE
39 in this situation, change the sensor range internally to 100 meters by entering PRANGE=100 in the SBE 39 (using
SEATERM). This changes the electronics’ operating range, allowing you to record pressure data at high elevations, but
slightly decreases resolution. After the data is recorded and uploaded, perform post-processing to adjust for the pressure
offset. Note that Sea-Bird software cannot currently perform this adjustment for the SBE 39.
CAUTION: Changing PRANGE in the SBE 39 does not increase the actual maximum water depth at which the
instrument can be used (20 meters) without damaging the sensor.
Example 1: You want to deploy the SBE 39 with a 20 m pressure sensor in a mountain lake at 1400 meters
(4590 feet). This is lower than 1570 meters shown in the table, so you do not need to adjust the sensor range.
After the data is recorded and uploaded, perform post-processing to adjust for the pressure offset.
Example 2: You want to deploy the SBE 39 with a 20 m pressure sensor in a mountain lake at 2000 meters
(6560 feet). This is higher than 1570 meters shown in the table, so you need to adjust the sensor range. In
SEATERM, set PRANGE=100 to allow use of the SBE 39 at this elevation. After the data is recorded and
uploaded, perform post-processing to adjust for the pressure offset.
SBE 26plus and 53
Unlike our other instruments that include a pressure sensor, the SBE 26plus and 53 output absolute pressure (i.e., at the
surface the output pressure is atmospheric pressure at the deployment elevation). Therefore, no corrections are required
when using these instruments above sea level. SBE 26plus / 53 software (SEASOFT for Waves) includes a module that
can subtract measured barometric pressures from tide data, and convert the resulting pressures to water depths.
5

Sea-Bird Electronics, Inc.
1808 136th Place NE
Bellevue, WA 98005
USA
Phone: (425) 643-9866
Fax: (425) 643-9954
E-mail: seabird@seabird.com
Web: www.seabird.com
APPLICATION NOTE NO. 75
August 2004
Maintenance of SBE 5T and 5M Pumps
This application note is intended to assist you in maintaining your SBE 5T or SBE 5M pump. A properly maintained
pump will provide constant flow for your CTD and any pumped auxiliary sensors, resulting in high quality data. The
main symptom of a non-functioning or poorly functioning pump is bad conductivity data, because the pump is not
pulling water through the conductivity cell.
CAUTION: Do not run the pump dry. The pump is water lubricated; running it without water will damage it. If
testing your system in dry conditions, remove the Tygon tubing from the hose barb at the top of the pump head, and fill
the inside of the pump head with water. This will provide enough lubrication to prevent pump damage during testing.
The application note is organized as follows:
Hose
barb
Pump
head
Routine rinsing after recovery (applies to both 5T and 5M)
SBE 5T Periodic cleaning for SBE 5T
Yearly maintenance for SBE 5T
Non-functioning or poorly functioning SBE 5T
Hose
barb
SBE 5M Periodic cleaning for SBE 5M
Yearly maintenance for SBE 5M
Non-functioning or poorly functioning SBE 5M
SBE
5M
SBE
5T
End cap
retaining
ring
(5T only)
Bulkhead
connector
Routine Rinsing after Recovery (applies to both 5T and 5M)
At the end of a day of taking casts:
1.
Remove the Tygon tubing from the pump head’s hose barbs.
2.
Leaving the pump head on the housing, thoroughly rinse the inside of the pump head, pouring clean, fresh water
through a hose barb. If the pump head is not rinsed between uses, salt crystals may form on the impeller. Over
time, this may freeze the impeller in place, preventing the pump from working.
3.
Replace the Tygon tubing on the hose barbs.
4.
Unscrew the cable locking sleeve from the bulkhead connector, and slide it up the
cable. Thoroughly rinse the cable connection (still mated) with clean, fresh water.
This will prevent premature cable failure.
5.
Slide the locking sleeve back into place, and screw it back onto the bulkhead
connector. Do not use a wrench or pliers to tighten the locking sleeve.
1
Locking sleeve

SBE 5T
Periodic Cleaning for SBE 5T
If you are going to store the pump for more than 1 week, or have removed the pump from a mooring, perform a more
thorough cleaning:
1.
Unscrew the pump head from the housing.
2.
Using clean, fresh water, thoroughly rinse the pump head and impeller.
3.
Inspect the impeller for salt deposits. Clean any deposits with clean, fresh water and a toothbrush. Verify that the
impeller can turn freely.
4.
Inspect the shaft, and the o-ring and thrust washer holding the impeller on the shaft. There is another thrust washer
underneath the impeller magnet, inside the housing. If this thrust washer is in good condition, you should observe a
small gap between the bottom of the impeller and the end cap. If there is no gap, the thrust washer is worn and
needs to be replaced (see Yearly Maintenance for SBE 5T for replacement procedure).
Note small gap
between impeller
and end cap.
Absence of gap
indicates worn
thrust washer
under impeller
magnet.
Impeller –
note salt
deposit
Shaft
Impeller
End cap
Shaft, o-ring,
and thrust
washer
End cap
SBE 5T with Pump Head Removed
2
End cap
o-ring

Yearly Maintenance for SBE 5T
1.
Unscrew the pump head from
the housing.
PN 30571
o-ring
End cap
PN 30009
2.
impeller/
Replace the o-ring and 2 thrust
PN
magnet
30010
washers on the shaft:
PN
thrust
30010
A. Remove the o-ring from the
PN
washer
thrust
shaft. A pair of tweezers works
30095
washer
well for this.
o-ring
B. Pull the impeller and attached
magnet off the shaft. The thrust
Shaft
washer above the impeller will
come off at the same time.
SBE 5T with Pump Head and Impeller Removed
Inspect the impeller for salt
build-up, and clean if
necessary. Inspect the magnet for wear. Particularly in sandy coastal environments, the magnet may be worn
down from abrasion. If necessary, replace the impeller / magnet assembly (PN 30009).
C. Remove the second thrust washer from the bottom of the shaft. A pair of tweezers works well for this.
D. Inspect the shaft for wear.
E. Rinse the shaft and depression in the housing with clean, fresh water. Allow to dry.
F. Using new thrust washers (2 of PN 30010) and o-ring (PN 30095), replace the thrust washer and impeller /
magnet on the shaft. Replace the other thrust washer and o-ring on the shaft, above the impeller, pushing hard
with your fingertip to seat the thrust washer and o-ring in place.
3.
Inspect the end cap o-ring and the mating surface on the pump head for dirt, nicks, and cuts. Clean or replace as
necessary. Apply a light coat of o-ring lubricant (Parker Super O Lube) to the o-ring and mating surfaces.
4.
Reinstall the pump head on the pump housing.
5.
Inspect the bulkhead connector for corrosion, which is a sign of seawater leakage between the bulkhead connector
and cable. If there is corrosion, thoroughly clean the connector with water, followed by alcohol. Inspect the
bulkhead connector for chips, cracks, or other flaws that may compromise the seal. Inspect the mating cable’s
connector for cuts, nicks, breaks, or other problems that may compromise the seal. Give the connector surfaces a
light coating of silicon grease, and remate the connector properly; see Application Note 57: I/O Connector Care
and Installation.
If the bulkhead connector is severely corroded or damaged, it must be replaced. Sea-Bird recommends that
this work be performed at the factory, because the pump’s physical configuration makes customerreplacement of the connector difficult.
3

Non-Functioning or Poorly Functioning SBE 5T
Perform the inspection procedures listed above in Yearly Maintenance for SBE 5T. If you do not discover the problem
there, proceed as follows.
Connector
end cap
Retaining ring
1.
Unscrew the connector end cap retaining ring. Pull out the
end cap and attached electronics from the housing.
2.
Verify that the magnet can spin freely and is not broken or
damaged.
3.
Look for other signs of damage on the electronics.
4.
Inspect the connector end cap o-ring and the mating surface in the housing for dirt, nicks, and cuts. Clean as
necessary. If the o-ring or mating surface is damaged, return the pump to Sea-Bird for repairs.
Sea-Bird recommends that connector end cap o-ring replacement be performed at the factory, because the
pump’s physical configuration makes customer-replacement of this o-ring difficult to perform without
special tools.
5.
Apply a light coat of o-ring lubricant (Parker Super O Lube) to the o-ring and mating surfaces. Gently place a new
desiccant bag on the electronics (see Application Note 71 for desiccant use and regeneration). Reinstall the
electronics in the housing, until the o-ring has fully seated. Reinstall the retaining ring on the connector end cap.
Housing
Magnet
Desiccant
4
PN 30082
Connector end
cap o-ring
Retaining ring

SBE 5M
Periodic Cleaning for SBE 5M
End cap
o-rings
If you are going to store the pump for more than 1 week, or have
removed the pump from a mooring, perform a more thorough cleaning:
CAUTION: Remove the end cap and impeller from the housing
before cleaning the impeller. The end cap o-rings seal the electronics
chamber. The end cap may walk out of the housing after the pump head
is removed, allowing water to enter the electronics chamber if you clean
the impeller without first removing the end cap from the housing.
End cap
and impeller
Pump
head
1.
Unscrew the pump head from the housing.
2.
Pull out the end cap from the housing.
3.
Using clean, fresh water, thoroughly rinse the pump head and impeller.
4.
Inspect the impeller for salt deposits. Clean any deposits with clean, fresh water and a toothbrush. Verify that the
impeller can turn freely.
5.
Inspect the shaft, and the o-ring and thrust washer holding the impeller on the shaft. There is another thrust washer
underneath the impeller magnet, inside the housing. If this thrust washer is in good condition, you should observe a
small gap between the bottom of the impeller and the end cap. If there is no gap, the thrust washer is worn and
needs to be replaced (see Yearly Maintenance for SBE 5M for replacement procedure).
6.
Apply a light coat of o-ring lubricant (Parker Super O Lube) to the o-ring and mating surfaces. Reinstall the end
cap in the housing, carefully aligning the end cap with the housing and pushing hard on the end cap to seat the first
o-ring in the housing (only 1 o-ring should now be visible).
CAUTION: If you are not careful, you may pinch the o-ring, which may allow water to enter the housing,
damaging the electronics.
7.
Reinstall the pump head on the end cap.
Note small gap
between impeller
and end cap.
Absence of gap
indicates worn
thrust washer
under impeller
magnet.
Impeller –
note salt
deposit
Shaft
End cap
Impeller
Shaft,
o-ring,
and
thrust
washer
End cap
SBE 5M with Pump Head Removed
5

Yearly Maintenance for SBE 5M
CAUTION: Remove the end cap and impeller from the housing
before cleaning the impeller. The end cap o-rings seal the electronics
chamber. The end cap may walk out of the housing after the pump head
is removed, allowing water to enter the electronics chamber if you clean
the impeller without first removing the end cap from the housing.
PN 31011
o-ring
PN 30571
o-ring
1.
Unscrew the pump head from the housing.
2.
Pull out the end cap from the housing.
3.
Replace the o-ring and 2 thrust washers on
the shaft:
End cap
A. Remove the o-ring from the shaft. A pair
PN 30009
of tweezers works well for this.
impeller/
PN
B. Pull the impeller and attached magnet off
magnet
30010
PN
the shaft. The thrust washer above the
thrust
30010
PN
impeller will come off at the same time.
washer
thrust
30095
Inspect the impeller for salt build-up, and
washer
o-ring
clean if necessary. Inspect the magnet for
wear. Particularly in sandy coastal
Shaft
environments, the magnet may be worn
down from abrasion. If necessary,
SBE 5M with Pump Head and Impeller Removed
replace the impeller / magnet assembly
(PN 30009).
C. Remove the second thrust washer from the bottom of the shaft. A pair of tweezers works well for this.
D. Inspect the shaft for wear.
E. Rinse the shaft and depression in the housing with clean, fresh water. Allow to dry.
F. Using new thrust washers (2 of PN 30010) and o-ring (PN 30095), replace the thrust washer and impeller /
magnet on the shaft. Replace the other thrust washer and o-ring on the shaft, above the impeller, pushing hard
with your fingertip to seat the thrust washer and o-ring in place.
4.
Inspect the end cap o-rings and the mating surface on the pump head for dirt, nicks, and cuts. Clean or replace as
necessary. Apply a light coat of o-ring lubricant (Parker Super O Lube) to the o-rings and mating surfaces.
5.
Reinstall the end cap in the housing, carefully aligning the end cap with the housing and pushing hard on the end
cap to seat the first o-ring in the housing (only 1 o-ring should now be visible).
CAUTION: If you are not careful, you may pinch the o-ring, which may allow water to enter the housing,
damaging the electronics.
6.
Reinstall the pump head on the end cap.
7.
Inspect the bulkhead connector for corrosion, which is a sign of seawater leakage between the bulkhead connector
and cable. If there is corrosion, thoroughly clean the connector with water, followed by alcohol. Inspect the
bulkhead connector for chips, cracks, or other flaws that may compromise the seal. Inspect the mating cable’s
connector for cuts, nicks, breaks, or other problems that may compromise the seal. Give the connector surfaces a
light coating of silicon grease, and remate the connector properly; see Application Note 57: I/O Connector Care
and Installation.
If the bulkhead connector is severely corroded or damaged, it must be replaced. Sea-Bird recommends that
this work be performed at the factory, because the pump’s physical configuration makes customerreplacement of the connector difficult.
End cap
and impeller
6
Pump
head

Non-Functioning or Poorly Functioning SBE 5M
Perform the inspection procedures listed above in Yearly Maintenance for SBE 5M. If you do not discover the problem
there, proceed as follows.
1.
Unscrew the pump head from the housing.
2.
Pull out the end cap from the housing.
3.
Pull out the electronics from the housing. Note that the electronics are wired to the bulkhead connector inside the
housing.
4.
Verify that the magnet can spin freely and is not broken or damaged.
5.
Look for other signs of damage.
6.
Apply a light coat of o-ring lubricant (Parker Super O Lube) to the o-ring and mating surfaces. Reinstall the
electronics in the housing. Reinstall the end cap in the housing, carefully aligning the end cap with the housing and
pushing hard on the end cap to seat the first o-ring in the housing (only 1 o-ring should now be visible).
CAUTION: If you are not careful, you may pinch the o-ring, which may allow water to enter the housing,
damaging the electronics.
7.
Reinstall the pump head on the end cap.
Magnet
Housing
PN 31011
o-ring
Electronics – wired to
bulkhead connector
inside housing
7
PN 30571
o-ring
End cap
and impeller
Pump
head

Sea-Bird Electronics, Inc.
1808 136th Place NE
Bellevue, WA 98005
USA
Phone: (425) 643-9866
Fax: (425) 643-9954
E-mail: seabird@seabird.com
Web: www.seabird.com
APPLICATION NOTE NO. 83
April 2006
Deployment of Moored Instruments
This Application Note applies to Sea-Bird instruments intended to provide time series data on a mooring or fixed site:
SBE 16plus and 16plus-IM SEACAT Conductivity and Temperature Recorder
SBE 19plus SEACAT Profiler CTD (in moored mode)
SBE 26plus SEAGAUGE Wave and Tide Recorder
SBE 37 (-IM, -IMP, -SM, -SMP, -SI, -SIP) MicroCAT Conductivity and Temperature Recorder
SBE 39 and 39-IM Temperature Recorder
SBE 53 BPR Bottom Pressure Recorder
We have developed a check list to assist users in deploying moored instruments. This checklist is intended as a guideline to
assist you in developing a checklist specific to your operation and instrument setup. The actual procedures and procedure
order may vary, depending on such factors as:
Instrument communication interface - RS-232, RS-485, or inductive modem
Deployment interface for RS-232 or RS-485 - with an I/O cable for real-time data or with a dummy plug for self-contained
operation
Sampling initiation - using delayed start commands to set a date and time for sampling to automatically begin or starting
sampling just before deploying the instrument
Sensors included in your instrument –
- Pressure is optional in the SBE 16plus, 16plus-IM, 37 (all), 39, and 39-IM.
- Conductivity is optional in the SBE 26plus and 53, and is not provided in the SBE 39 and 39-IM.
- Optional auxiliary sensors can be integrated with the SBE 16plus, 16plus-IM, and 19plus.
Deployment Summary
Instrument serial number
Mooring number
Date of deployment
Depth of instrument
Intended date of recovery
Capture file printout(s) attached, or file
name and location (showing status
command, calibration coefficients command if
applicable, any other applicable commands)
Actual date of recovery
Condition of instrument at recovery
Notes
1

Preparation for Deployment
Task
If applicable, upload existing data in memory.
Perform preliminary processing / analysis of data to ensure you have uploaded all data, that data was not
corrupted in upload process, and that (if uploading converted data) instrument EEPROM was programmed
with correct calibration coefficients. If there is a problem with data, you can try to upload again now. Once
you record over data in next deployment, opportunity to correct any upload problem is gone.
Initialize memory to make entire memory available for recording.
If memory is not initialized, data will be stored after last recorded sample.
Calculate battery endurance to ensure sufficient power for intended sampling scheme.
See instrument manual for example calculations.
Calculate memory endurance to ensure sufficient memory for intended sampling scheme.
See instrument manual for example calculations.
Install fresh batteries.
Even if you think there is adequate battery capacity left for another deployment, cost of fresh batteries is
small price to pay to ensure successful deployment.
Establish setup / operating parameters.
1. Click Capture button in SEATERM and enter file name to record instrument setup, so you have
complete record of communication with instrument.
2. Set current date and time.
3. Establish setup / operating parameters.
4. If desired, set date and time for sampling to automatically begin.
5. Send Status command (DS or #iiDS) to verify and provide record of setup. **
6. Send Calibration Coefficients command (DC, #iiDC, DCAL, or #iiDCAL) to verify and provide
record of calibration coefficients. **
Get conductivity sensor ready for deployment:
Remove protective plugs that were placed in Anti-Foulant Device caps or remove Tygon tubing that was
looped end-to-end around conductivity cell to prevent dust / dirt from entering cell.
Note: Deploying instrument with protective plugs or looped Tygon tubing in place will prevent instrument
from measuring conductivity during deployment, and may destroy cell.
Install fresh AF24173 Anti-Foulant Devices for conductivity sensor.
Rate of anti-foul use varies greatly, depending on location and time of year. If you think there is adequate
capability remaining, and previous deployment(s) in this location and at this time of year back up that
assumption, you may not choose to replace Anti-Foulant Devices for every deployment. However, as for
batteries, cost of fresh Anti-Foulant Devices is small price to pay to ensure successful deployment.
For instrument with external pump (16plus, 16plus-IM, 19plus), verify that system plumbing is
correctly installed.
See instrument manual for configuration.
Start sampling (if you did not set up instrument with a delayed start command), or verify that
sampling has begun (if you set up instrument with a delayed start command).
1. Click Capture button in SEATERM and enter file name to record instrument setup, so you have a
complete record of communication with instrument.
2. If you did not set up instrument with a delayed start command, send command to start sampling.
3. Send Status command (DS or #iiDS) to verify and provide record that instrument is sampling. **
4. Send Send Last command (SL or #iiSL) to look at most recent sample and verify that output looks
reasonable (i.e., ambient temperature, zero conductivity, atmospheric pressure). **
5. If instrument has pressure sensor, record atmospheric pressure with barometer. You can use this
information during data processing to check and correct for pressure sensor drift, by comparing to
instrument’s pressure reading in air (from Step 4).
Note: For instrument with pump (external or integral), avoid running pump dry for extended period of
time.
If cable connectors or dummy plugs were unmated, reinstall cables or dummy plugs as described in
Application Note 57: I/O Connector Care and Installation.
Failure to correctly install cables may result in connector leaking, causing data errors as well as damage to
bulkhead connector.
Install mounting hardware on instrument.
Verify that hardware is secure.
** Note: Actual instrument command is dependent on communication interface and instrument.
2
Completed?

Recovery
Immediately upon recovery
Task
Rinse instrument with fresh water.
Remove locking sleeve on dummy plug or cable, slide it up cable (if applicable), and rinse connection
(still mated) with fresh water.
For instrument with pump (external or integral), stop sampling.
Completed?
Connect to instrument in SEATERM and send command to stop sampling (STOP or #iiSTOP). Stop sampling as soon
as possible upon recovery to avoid running pump dry for an extended period of time. **
If instrument has pressure sensor, record atmospheric pressure with barometer.
You can use this information during data processing to check and correct for pressure sensor drift, by comparing to
instrument’s pressure reading in air.
Gently rinse conductivity cell with clean de-ionized water, drain, and gently blow through cell to
remove larger water droplets.
If cell is not rinsed between uses, salt crystals may form on platinized electrode surfaces. When instrument is used
next, sensor accuracy may be temporarily affected until these crystals dissolve.
Note that vigorous flushing is not recommended if you will be sending instrument to Sea-Bird for postdeployment calibration to establish drift during deployment.
For instrument with external pump (16plus, 16plus-IM, 19plus): Remove Tygon tubing from pump
head’s hose barbs, and rinse inside of pump head, pouring fresh water through a hose barb.
If pump head is not rinsed between uses, salt crystals may form on impeller. Over time, this may freeze impeller in
place, preventing pump from working.
Install protective plugs in Anti-Foulant Device caps or loop Tygon tubing end-to-end around
conductivity cell for long term storage.
This will prevent dust / dirt from entering conductivity cell.
Note: For short term (less than 1 day) storage, see Application Note 2D: Instructions for Care and Cleaning of
Conductivity Cells.
Upload data in memory.
1.
2.
3.
4.
Connect to instrument in SEATERM.
If you have not already done so, send command to stop sampling (STOP or #iiSTOP). **
Upload data in memory, using Upload button in SEATERM.
Perform preliminary processing / data analysis to ensure you have uploaded all data, data was not corrupted in
upload process, and (if uploading converted data) instrument EEPROM was programmed with correct calibration
coefficients. If there is a problem with data, you can try to upload again now. Once you record over data in next
deployment, opportunity to correct any upload problem is gone.
** Note: Actual instrument command is dependent on communication interface and instrument.
Later
Task
Completed?
Clean conductivity cell, as needed:
Do not clean cell if you will be sending instrument to Sea-Bird for post-deployment calibration to establish drift
during deployment.
Clean cell if you will not be performing a post-deployment calibration to establish drift.
See cleaning instructions in instrument manual and Application Note 2D: Instructions for Care and Cleaning of
Conductivity Cells.
For instrument with external pump (16plus, 16plus-IM, 19plus): Clean pump as described in
Application Note 75: Maintenance of SBE 5T and 5M Pumps.
(Annually) Inspect and (if applicable) rinse pressure port.
See instructions in instrument manual.
Send instrument to Sea-Bird for calibrations / regular inspection and maintenance.
We typically recommend that instrument be recalibrated once a year, but possibly less often if used only occasionally.
We recommend that you return instrument to Sea-Bird for recalibration. In between laboratory calibrations, take field
salinity samples to document conductivity cell drift.
Notes:
1. We cannot place instrument in our calibration bath if heavily covered with biological material or painted with antifoul paint. Remove as much material as possible before shipping to Sea-Bird; if we need to clean instrument before
calibrating it, we will charge you for cleaning. To remove barnacles, plug ends of conductivity cell to prevent
cleaning solution from getting into cell, then soak instrument in white vinegar for a few minutes. To remove antifoul paint, use Heavy Duty Scotch-Brite pad or similar material.
2. If using lithium batteries, do not ship batteries installed in instrument. See
http://www.seabird.com/customer_support/LithiumBatteriesRev2005.htm for shipping details.
3

Sea-Bird Electronics, Inc.
1808 136th Place NE
Bellevue, WA 98005
USA
Phone: (425) 643-9866
Fax: (425) 643-9954
E-mail: seabird@seabird.com
Web: www.seabird.com
APPLICATION NOTE NO. 84
July 2006
Using Instruments with Druck Pressure Sensors in
Muddy or Biologically Productive Environments
This Application Note applies to Sea-Bird instruments with Druck pressure sensors, for moored applications or other long
deployments that meet either of the following conditions:
used in a high-sediment (muddy) environment, in a pressure sensor end up orientation
used in a biologically productive environment, in any orientation
Standard pressure sensor port plug
At Sea-Bird, a pressure port plug with a small (0.042-inch diameter)
vent hole in the center is inserted in the pressure sensor port. The vent hole
allows hydrostatic pressure to be transmitted to the pressure sensor inside
the instrument.
If the instrument is deployed in a high-sediment (muddy) environment
with the pressure sensor end up, the pressure port may partially fill
with sediment (through the vent hole) over time, causing a delay in the
pressure response.
If the instrument is deployed in a biologically productive environment,
the vent hole may be covered with biological growth over time, causing a
delay in the pressure response, or in extreme cases completely blocking
the pressure signal.
Note: Photo is for an SBE 37-SM. Pressure port details are similar for all instruments included in this application note.
Sea-Bird has developed a high-head pressure port plug for deployment in muddy and/or
biologically productive environments. The high-head plug extends beyond the surface of
the instrument end cap, and has four horizontal vent holes connecting internally to a vertical
vent hole.
The horizontal orientation of the external holes prevents the deposit of sediment inside
the pressure port.
Each of the four vent holes is larger (0.062-inch vs. 0.042-inch diameter) than the
single vent hole in the standard pressure port plug, significantly reducing the possibility
that biological growth will cover all of the hole(s).
To purchase the high-head pressure port plug, Part Number 233186, contact Sea-Bird.
Vent hole
(typical)
High-Head
Pressure Port Plug,
Part Number 233186
High-Head Pressure Port Plug Installation
1.
2.
3.
Unscrew the standard pressure port plug from the pressure port.
Rinse the pressure port with warm, de-ionized water to remove any particles, debris, etc. Do not put a brush or any
object in the pressure port; doing so may damage or break the pressure sensor.
Install the high-head pressure port plug in the pressure port.
Note: Until several years ago, Sea-Bird filled the pressure port with silicon oil at the factory. For Druck pressure sensors,
we determined that this was unnecessary, and no longer do so. It is not necessary to refill the oil in the field. However, for
Paine or Paroscientific Digiquartz pressure sensors, the pressure port does need to be refilled with silicon oil. Please
contact Sea-Bird with the serial number of your instrument if you are unsure of the type of pressure sensor installed in
your instrument.
1

Sea-Bird Electronics, Inc.
1808 136th Place NE
Bellevue, WA 98005
USA
Phone: (425) 643-9866
Fax: (425) 643-9954
E-mail: seabird@seabird.com
Web: www.seabird.com
Application Note 56
Revised September 2003
Interfacing to RS-485 Sensors
A few Sea-Bird instruments use the RS-485 protocol for transmitting setup commands to the instrument and
receiving data from the instrument. However, most personal computers (PCs) do not come with an RS-485 port.
This Application Note covers interfacing our RS-485 instruments with a PC by the following methods:
Connecting the instrument to an external RS-485/RS-232 Interface Converter that plugs into an existing
RS-232 port on the PC.
OR
Installing an RS-485 interface card (and associated software) in the PC, and then connecting the instrument
directly to the new RS-485 port in the PC.
External RS-485/RS-232 Interface Converter
RS-485/RS-232 Interface Converters are available commercially. These converters plug into the RS-232 port on the PC,
and allow an RS-485 device to be connected through the converter. Sea-Bird tested a converter from one manufacturer
with our instruments, and verified compatibility. The manufacturer and tested converter is:
Black Box (www.blackbox.com) –
IC520A-F with RS-232 DB-25 female connector and RS-485 terminal block connector
Other converters from this manufacturer, and converters from other manufacturers, may also be compatible with
Sea-Bird instruments. We recommend testing other converters with the instrument before deployment, to verify that there
is no problem.
Follow this procedure to use the IC520A-F Converter:
1.
Connect the Converter to the PC:
If the PC has a 25-pin male RS-232 connector, plug the Converter directly into the PC connector.
If the PC has a 9-pin male RS-232 connector, plug the Converter into a 25-pin to 9-pin adapter
(such as Black Box FA520A-R2 Adapter). Plug the 25-pin to 9-pin adapter into the PC.
2.
On the Converter, measure the voltage between XMT+ and ground and between XMT- and ground.
Connect whichever has the highest voltage to RS-485 ‘A’ and the other to RS-485 ‘B’. The ground terminal can
be left unconnected.
RS-485 Interface Card and Port in the PC
An RS-485 Interface Card installs in the PC, and allow an RS-485 device to be connected to the RS-485 port.
These Interface Cards are available commercially. When using with a Sea-Bird instrument:
RS-485 Transmitter The Interface Card must be configured to automatically handle the RS-485 driver enable.
Two-Wire Interface TX+ and RX+ on the Interface Card must be connector together and to ‘A’ on the instrument.
TX- and RX- on the Interface Card must be connected together and to ‘B’ on the instrument.
Note: Some Interface Cards have a jumper to make the connections internally, while for other Cards the
connections must be made in a jumper cable.
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Terminal Program Compatibility If the Interface Card uses shared interrupts, SEATERM (our Windows terminal program) must be used to
communicate with the instrument.
If the Interface Card is configured as a standard COM port, either SEATERM or our DOS-based terminal
programs may be used to communicate with the instrument.
Sea-Bird tested two Interface Cards from one manufacturer with our instruments, and verified compatibility.
The manufacturer and tested cards are:
National Instruments (www.ni.com) AT-485/2
PCI-485/2
Other Cards from this manufacturer, and Cards from other manufacturers, may also be compatible with Sea-Bird
instruments. We recommend testing other Cards with the instrument before deployment, to verify that there is
no problem.
Follow this procedure to use the AT-485/2 or PCI-485/2 Interface Card:
1.
Install the RS-485 driver software (provided with Interface Card) on your PC before installing the
Interface Card.
2.
Install the RS-485 Interface Card.
3.
Configure the RS-485 Interface Card in your PC (directions are for a PC running Windows XP):
A. Right click on My Computer and select Properties.
B. In the System Properties dialog box, click on the Hardware tab. Click the Device Manager button.
C. In the Device Manager window, double click on Ports. Double click on the desired RS-485 port.
D. In the Communications Port Properties dialog box, click the Port Settings tab.
Click the Advanced button.
E. In the Advanced Settings dialog box, set Transceiver Mode to 2 wire TxRdy Auto.
4.
Make a jumper cable (do not use a standard adapter cable) to connect the Interface Card to the instrument’s
I/O cable. Pin outs are shown for a Sea-Bird 9-pin (current production) or 25-pin (older production) I/O cable:
DB-9S
(connect to PC)
pin 1 common
pin 4 TX+
pin 8 RX+
pin 5 TXpin 9 RX5.
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DB-9P
(connect to Sea-Bird I/O cable PN 801385)
pin 5 common
pin 3 'A'
pin 3 'A'
pin 2 'B'
pin 2 'B'
DB-25P
(connect to Sea-Bird I/O cable PN 801046)
pin 7 common
pin 2 'A'
pin 2 'A'
pin 3 'B'
pin 3 'B'
Run SEATERM (these Cards use shared interrupts, so the DOS terminal programs cannot be used):
A. In SEATERM’s Configure menu, select the desired instrument.
B. In the Configuration Options dialog box, set Mode to RS-485 and set COMM Port to the appropriate
RS-485 port.
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Sea-Bird Electronics, Inc.
1808 136th Place NE
Bellevue, WA 98005
USA
Phone: (425) 643-9866
Fax: (425) 643-9954
E-mail: seabird@seabird.com
Web: www.seabird.com
APPLICATION NOTE NO. 40
Revised May 2005
SBE 5T PUMP SPEED ADJUSTMENT INSTRUCTIONS
Equipment: DC power supply
Frequency counter
Drawings:
31441B (schematic)
41250A (assembly)
The pump housing must be disassembled to adjust the pump speed. Referencing above drawings:
1. Remove the white plastic end cap retainer ring located at the connector end of the pump by twisting in a
counter-clockwise motion.
2. Install a 2-pin dummy plug with locking sleeve over the bulkhead connector to provide a good grip on
the pump connector and protect the connector pins. Rotate the connector back and forth while carefully
pulling the end cap away from the housing. Pull the end cap (piston o-ring seal) out of the housing. The
motor and electronics assembly are attached to the end cap and will come out as a unit.
3. Connect the positive lead of your frequency counter to the yellow test post (T1) (drawing 41250A).
Connect the frequency counter ground (negative) to the power supply ground (negative).
4. Supply power:
Low voltage pump (pump with LV in the serial number) - Supply 6 volts DC power to the
bulkhead connector (large pin is common, small pin is positive) or directly to the PCB
(P8 is positive, P19 or P18 is common, drawing 41250A).
Normal voltage pump - Supply 12 volts to the bulkhead connector (large pin is common, small pin
is positive) or directly to the PCB (P8 is positive, P19 or P18 is common, drawing 41250A).
5. A 2K ohm potentiometer (R11, drawing 41250A) is located on the back side of the board. Adjust the
potentiometer to obtain the frequency corresponding to the desired speed (Frequency * 30 = rpm):
Pittman 18.2 motor (P/N 3711B113-R1) - Set jumper position P15 to P17 (1300 rpm) and P12
to P13 (1300 rpm), and adjust the speed as desired, up to the nominal maximum of 2000 rpm.
Pittman 7.4 motor (P/N 3711B112-R1) - Set jumper position P15 to P16 (3000 rpm) and P14
to P13 (3000 rpm), and adjust the speed as desired, up to the nominal maximum of 4500 rpm.
To adjust speed below approximately 2200 rpm, set jumper position P15 to P17 (1300 rpm) and
P12 to P13 (1300 rpm), and adjust speed using the potentiometer.
Pittman 3.55 motor (P/N 3711B112-R2) - Set jumper position P15 to P16 (3000 rpm) and P14
to P13 (3000 rpm), and adjust the speed as desired, up to the nominal maximum of 4500 rpm.
To adjust speed below approximately 2200 rpm, set jumper position P15 to P17 (1300 rpm) and
P12 to P13 (1300 rpm), and adjust speed using the potentiometer.
6. Disconnect the frequency counter and the power supply. Make sure the O-ring and mating surfaces
are clean. Lightly lubricate the o-ring before inserting the connector end cap into the housing. Replace
the pump end cap retainer.
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