MicroCAT C-T-DO (P optional) Sensor
SBE 37-SIP-IDO (Serial Interface, integral Pump, & Integrated Dissolved Oxygen)

Print version     Current manual - RS-232 or RS-485 (not yet available) (older manuals)    Reference Sheet - RS-232 or RS-485 (not yet available)     Configuration options & accessories

SUMMARY

• Conductivity, Temperature, Pressure (optional), and Dissolved Oxygen measurements, at user-programmable 1-sec to 6-hour intervals.
• RS-232 or RS-485 serial interface, internal memory, and external power.
• Adaptive Pump Control for high-accuracy oxygen data.
• Expendable anti-foulant devices, unique flow path, and pumping regimen for maximum bio-fouling protection.
• Depths to 350 meters (ShallowCAT plastic housing) or 7000 meters (titanium housing).
• Sea-Bird's field-proven MicroCAT family, with more than 10,000 instruments deployed since 1997.
• Five-year limited warranty.

DESCRIPTION

The SBE 37-SIP-IDO MicroCAT is a high-accuracy conductivity and temperature (pressure optional) sensor with Serial Interface, integral Pump, and Integrated Dissolved Oxygen sensor. It includes an internal memory, but is externally powered. Constructed of non-corroding materials for long life with minimal maintenance, the MicroCAT is useful as a stand-alone monitoring device, and is easily integrated with current meters, ROVs, AUVs, towed sonars, and other instrumentation platforms.

Calibration coefficients are stored in EEPROM, allowing output of C, T, P, DO, and time in ASCII engineering units (decimal or XML; raw output available); time, salinity, sound velocity (Chen-Millero), and depth can also be output.

SENSORS

Temperature and Conductivity sensors are based on our field-proven SeaCAT and SeaCATplus. Electrical isolation of conductivity electronics eliminates any possibility of ground-loop noise. Our unique internal-field conductivity cell permits the use of expendable anti-foulant devices, for long-term bio-fouling protection. The aged and pressure-protected thermistor has a long history of exceptional accuracy and stability.

The IDO is a frequency-output version of our field-proven SBE 43 Dissolved Oxygen sensor, with the same performance specifications.

The optional strain-gauge pressure sensor is available in eight ranges, to a maximum depth of 7000 meters. Compensation of the temperature influence on pressure is performed by the MicroCAT’s CPU.

The integral pump runs each time the MicroCAT samples, providing the following advantages:

• Improved conductivity and oxygen response – The pump flushes the previously sampled water from the conductivity cell and oxygen sensor plenum, and brings a new water sample quickly into the system.
• Improved anti-foul protection – Water does not freely flow through the conductivity cell between samples, allowing the anti-foul concentration inside the system to maintain saturation.
• Improved measurement correlation – The individually calibrated SBE 43 Dissolved Oxygen sensor is integrated within the CTD flow path, providing optimum correlation with CTD measurements.

With Adaptive Pump Control, the MicroCAT calculates the pumping time for best oxygen accuracy as a function of the previous sample's temperature and pressure (maximizing data quality while minimizing power consumption).

COMMUNICATIONS AND INTERFACING

The MicroCAT communicates via RS-232 or RS-485 serial interface:

• RS-232 – Real-time data can be transmitted up to 1600 meters at 600 baud (power considerations may limit distance), simultaneous with recording. Data can be uploaded at up to 115.2K baud. The user can upgrade firmware through the external connector, without opening the housing.

• RS-485 – Multiple MicroCATs can share a common 4-wire cable (power, common, data +, data -), minimizing cable complexity for C-T chains.

User-selectable operating modes include:

• Autonomous – The MicroCAT is pre-programmed to sample, store data in memory, and transmit data. There are three types of autonomous sampling:
  - Continuous -- Pump continuously and sample continuously at 1 Hz (1 sample/sec).
  - Fast Interval -- Pump continuously and sample at 5-sec to 179-sec intervals.
  -Slow Interval -- Pump runs before each sample, and samples at 3-minute to 6-hour intervals.
• Polled  – On command from a computer or satellite, radio, or wire telemetry equipment, the MicroCAT runs the pump, samples, and transmits data.
• Serial Line Sync – In response to a pulse on the serial line, the MicroCAT wakes up, runs the pump, takes 1 sample, stores data in memory, transmits data, and goes to sleep.

SOFTWARE

The MicroCAT is supplied with a powerful Windows software package, Seasoft^© V2, which includes:

• SeatermV2^© – terminal program for easy communication and data retrieval.
• SBE Data Processing^© – programs for calculation, display, and plotting of conductivity, temperature, pressure (optional), dissolved oxygen, and derived variables such as salinity, sound velocity, and density.

SPECIFICATIONS

Clock Stability: 5 sec/month

Memory: 8 Mbyte; capacity in excess of 444,000 samples with pressure

Acquisition Time: 2.2 - 5.0 sec/sample, dependent on sampling mode and inclusion of pressure sensor

Input Power: 0.25 Amps at 9 - 24 VDC

Power Consumption (all with pressure)*:

   Quiescent: 0.0004 Watts

   CTD-DO Sample Acquisition (excluding pump): 0.17 Watts

   CTD-DO Sample Waiting (not sampling, pump running, excluding pump):
      Receive line valid 0.056 Watts
      Receive line not valid 0.016 Watts

   CTD-DO Between Samples:
      Receive line valid 0.056 Watts
      Receive line not valid 0.0004 Watts

   Pump: 0.12 Watts

   Communications: 0.065 Watts

* Power consumption values are for RS-232 interface; for RS-485 interface, see RS-485 manual.

Housing, Depth Rating, Weight:

Dimensions

Connector (RS-232 shown. For RS-485: pin 2 is RS-485A, pin 3 is RS-485B):

ADDITIONAL INFORMATION / LINKS:

Documentation -- manual, photos, technical papers, application notes, etc.

• Current product manual -- RS-232 and RS-485 (not yet available) (older manuals)
• Photo Gallery
• Print version of this specification sheet / brochure
• Application Notes:
  - 6: Determination of Sound Velocity from CTD Data
  - 10: Compressibility Compensation of Sea-Bird Conductivity Sensors
  - 14: 1978 Practical Salinity Scale
  - 27Druck: (Druck) Strain Gauge Pressure Sensor Error Sources
  - 42: ITS-90 Temperature Scale
  - 56: Interfacing to RS-485 Sensors
  - 64: SBE 43 Dissolved Oxygen Sensor -- Background Information, Deployment Recommendations, and Cleaning and Storage
  - 68: Using USB Ports to Communicate with Sea-Bird Instruments
  - 69: Conversion of Pressure to Depth
  - 71: Desiccant Use and Regeneration (drying)
  - 73: Using Instruments with Pressure Sensors at Elevations Above Sea Level
  - 83: Deployment of Moored Instruments
  - 90: Absolute Salinity and TEOS-10: Sea-Bird's Implementation Plans
• Sea-Bird webinar -- Introduction to Sea-Bird, Long-Term Deployments with Moored CTDs, and CTD Profilers

Sales Information -- options, accessories, cables, mount kits, spares, etc.

• Configuration options & accessories:
  - Details for SBE 37-SIP-IDO
  - Listing for all products
• Cables
• Mount kits
• Spare parts
• Ads:
  - Bringing Integrated Dissolved Oxygen to Sea-Bird SBE 37 MicroCAT Moored CTDs
  - Moored Salinity? Stop the Flow to Prevent Drift
  - Get More Data per Dollar on your Shallow Moorings

Software -- components of Seasoft V2

• SeatermV2 -- description, download
• SBE Data Processing -- description, download

Links to Other Instruments of Interest

• Other MicroCATs (compare features):
  - 37-SM (Serial interface & Memory)
  - 37-SMP (Serial interface, Memory, & integral Pump)
  - 37-SMP-IDO (Serial Interface, Memory, integral Pump, & Integrated Dissolved Oxygen)  (membrane-type DO sensor)
  - 37-SMP-ODO (Serial interface, Memory, integral Pump, & integrated Optical Dissolved Oxygen)
  - 37-SI (Serial Interface)
  - 37-SIP (Serial Interface & integral Pump)
  - 37-SIP-ODO (Serial Interface, integral Pump, & integrated Optical Dissolved Oxygen) -- coming soon
  - 37-IM (Inductive Modem)
  - 37-IMP (Inductive Modem & integral Pump)
  - 37-IMP-IDO (Inductive Modem, integral Pump, & Integrated Dissolved Oxygen)  (membrane-type DO sensor)
  - 37-IMP-ODO (Inductive Modem, integral Pump, & integrated Optical Dissolved Oxygen)
• SBE 16plus V2 (serial interface) and 16plus-IM V2 (Inductive Modem interface) -- moored CTDs that can acquire data from auxiliary sensors

Specifications are subject to change without notice.

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