MicroCAT C-T (P optional)
SensorSBE 37-SI (Serial Interface)
MicroCAT C-T (P optional)
Sensor![[HRule Image]](../../images/div.gif){kind=small}
Print version
Current manual - RS-232 or
RS-485 (older
manuals)
Reference Sheet -
RS-232 or
RS-485
Configuration options & accessories
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SUMMARY
DESCRIPTION
The SBE 37-SI MicroCAT is a high-accuracy conductivity and temperature (pressure optional) sensor with Serial Interface, which includes a non-volatile FLASH memory. Externally powered, it is useful as a stand-alone monitoring device, and is easily integrated with current meters, ROVs, AUVs, towed sonars, and other instrumentation platforms. Constructed of non-corroding materials to ensure long life with minimum maintenance, the MicroCAT is rated for operation to 350 meters (plastic ShallowCAT housing) or 7000 meters, or pressure sensor full-scale range.
Calibration coefficients are stored in EEPROM, allowing the MicroCAT to output data in ASCII engineering units (decimal or XML format); raw output is also available. Data always includes Conductivity, Temperature, and (optional) Pressure; time, sound velocity (Chen-Millero), salinity, depth, and density can also be output.
SENSORS AND SENSOR INTERFACE ELECTRONICS
The MicroCAT retains the temperature and conductivity sensors used in our time-proven SeaCAT and SeaCATplus. Electrical isolation of the conductivity electronics eliminates any possibility of ground-loop noise. The unique internal-field conductivity cell permits the use of expendable anti-foulant devices. The aged and pressure-protected thermistor has a long history of exceptional accuracy and stability.
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 offset and scale is performed by the MicroCAT's CPU.
Temperature is acquired by applying an AC excitation to a hermetically sealed VISHAY reference resistor and an ultra-stable aged thermistor (drift rate typically < 0.002 °C/year). The ratio of thermistor resistance to reference resistance is determined by a 24-bit A/D converter, which also processes the pressure sensor signal. Conductivity is acquired using an ultra-precision Wien-Bridge oscillator.
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:
- Continuous sampling at the fastest rate possible (1.0 sec minimum without pressure)
- Interval sampling at 6-sec to 6-hour intervals.
SOFTWARE
The MicroCAT is supplied with a powerful Windows software package, Seasoft© V2, which includes:
SPECIFICATIONS
|
Measurement Range |
Initial Accuracy |
Typical Stability |
Resolution | |
| Conductivity |
0
to 7 S/m (0 to 70 mS/cm) |
± 0.0003 S/m (0.003 mS/cm) |
0.0003 S/m (0.003 mS/cm) per month |
0.00001 S/m (0.0001 mS/cm) |
|
Temperature (°C) |
-5 to 45 |
± 0.002
(-5 to 35 °C); ± 0.01 (35 to 45 °C) |
0.0002 per month | 0.0001 |
| Optional Pressure |
20 / 100 / 350 /
600 /
1000 / 2000 / 3500 / 7000 m (meters of deployment depth capability) |
± 0.1% of full scale range | 0.05% of full scale range per year | 0.002% of full scale range |
Clock Stability: 5 sec/month
Memory: 8 Mbyte; capacity in excess of 530,000 samples
Input Power: 0.5 Amps at 8.5 - 24 VDC
Quiescent Current: 30 microamps *
Communication Current: 4.3 milliamps *
Acquisition Current: 15 milliamps *
* Power consumption values are for RS-232 interface; for RS-485 interface, see RS-485 manual.
Acquisition Time: 1.0 - 2.6 sec/sample, dependent on sampling mode and inclusion of pressure sensor
Housing, Depth Rating, and Weight (without pressure sensor or clamps):
| Housing Material | Depth Rating | Weight |
| Plastic | 350 m (1148 ft) |
2.2 kg (4.9 lbs) in
air 1.2 kg (2.7 lbs) in water |
| Titanium | 7000 m (23,000 feet) |
2.9 kg (6.5 lbs) in
air 1.9 kg (4.3 lbs) in water |
Dimensions: in millimeters (inches)
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.
Sales Information -- options, accessories, cables, mount kits, spares, etc.
Software -- components of Seasoft V2
Links to Other Instruments of Interest
Specifications are subject to change without notice.
Sea-Bird Home Phone: (+1) 425-643-9866 E-mail: seabird@seabird.com
