Print version Current Manual - SBE 21 & Interface Box (older manuals) Configuration options & accessories
The SBE 21 accurately determines sea surface temperature and conductivity from underway vessels. Data is simultaneously stored in memory and transmitted to a computer serial port, allowing independent data logging and real-time data acquisition. Typically mounted near the ship's seawater intake, the SBE 21 is connected to an AC-powered interface box positioned near the computer. The interface box provides power and an isolated data interface, and contains a NMEA 0183 port for appending navigation information to the data stream.
For corrosion resistance, only plastic, titanium, and the glass/platinum cell are exposed to seawater. Valves control seawater circulation and fresh water flushing. The sensor assembly is easily removed for cleaning and calibration.
TEMPERATURE & CONDUCTIVITY SENSORS
The sensors are mounted in a PVC water jacket assembly:
Bulkhead connectors are provided (standard) for optional auxiliary sensors:
Acquisition and display of auxiliary sensor data is fully supported in our software.
The SBE 21 samples using one of the following user-programmable schemes:
When the SBE 21 memory fills, real-time output continues after internal recording stops. When a computer cannot be dedicated to data logging, the SBE 21's internal memory permits autonomous operation with periodic downloading.
Firmware upgrades can be downloaded through the communications port by the user, without opening the electronics.
Seasoft© V2, our complete Windows 2000/XP software package, is included at no charge. Its modular programs include:
The PVC base or back plate may be drilled for mounting to the ship. Seawater connections (for normal use) and fresh water connections (for cleaning) are PVC pipes with 1-inch (25.4-mm) U.S. standard NPT threads. Mating female fittings are provided, and can easily be adapted to locally available pipe sizes. A stainless steel and plastic in-line pipe mount is available for safe below-waterline installation of the remote temperature sensor.
MEMORY & DATA FORMAT
The SBE 21 has a 64 Mbyte FLASH RAM memory. Each sample of temperature and conductivity uses 6 bytes. Remote temperature (if enabled) adds 3 bytes per sample, and each optional A/D voltage adds 2 bytes. Inter-record headers, written each 10,000 samples, contain sample numbers, data pointers, and time/date from the SBE 21's internal real-time clock.
PN 90488 SEACAT/SEALOGGER RS-232 & NAVIGATION INTERFACE BOX
A 100-250 VAC-powered interface box supplies isolated DC power, provides an optically-coupled RS-232 standard interface to the user's computer, and permits the appending of navigation data via a NMEA 0183 interface port. Each sample (including primary and remote temperature, conductivity, and analog voltages) is transmitted via the interface box, where navigation information (converted to a uniform format from a wide range of receiver types) is appended prior to transfer to the computer. A 10-meter cable for connecting the SBE 21 to the interface box, AC power cord, and 1.5-meter cable for connecting the interface box to the computer are also supplied.
|Measurement Range||Initial Accuracy||Resolution|
0 - 7 S/m
(0 - 70 mmho/cm)
± 0.001 S/m
|-5 to +35||± 0.01||0.001|
SBE 38 remote (°C)
|-5 to +35||± 0.001||0.0003|
3 seconds or longer in steps of 1 second
Water jacket volume: ~ 5 liters
Recommended flow rate: ~ 1 liter per second
Water jacket pressure limit: 34.5 decibars (50 psi)
Dimensions: 577 mm high x 483 mm wide x 229 mm (22.7 x 19.0 x 9.0 in.)
Shipping weight: 41 kg (90 lbs)
Note: Seasave also supports acquisition of data from a NMEA device connected
directly to computer (instead of Interface Box).
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 Skype: sea-bird-electronics E-mail: email@example.com