Section 2: Description of SBE 38
6
Section 2: Description of SBE 38
This section describes the functions and features of the SBE 38, including
specifications and dimensions.
System Description
Sophisticated A/D acquisition electronics, ultra-stable thermistor, and state-of-
the-art calibration provide the standards-level performance of an expensive
AC bridge and platinum thermometer at a small fraction of the cost. The
SBE 38 is unaffected by shock and vibration, has high accuracy and stability,
and is easy to use. It has a rugged, corrosion-proof, 10,500 meter (34,400 foot)
titanium pressure housing. Real-time temperature data is transmitted in ASCII
characters (in °C or raw counts) via an RS-232 or optional RS-485 serial
interface for display or logging by PC or data logger.
The standard measurement range is -5 to +35 °C. An optional range of -5 to
+50 °C is available at slightly reduced accuracy and resolution. For the
standard range, absolute accuracy is better than 0.001 °C (1 mK) and
resolution is approximately 0.00025 °C (0.25 mK). Each sensor includes
certification that demonstrates drift of less than 0.001 °C (1 mK) during a
six-month period.
Applications include calibration baths, oceanographic/aquatic research, and
environmental monitoring.
The SBE 38 operates in one of three ways:
•RS-232 (full duplex) with one SBE 38 connected to the interface
•RS-485 (half duplex) with one SBE 38 connected to the interface
•RS-485 (half duplex) with several RS-485 sensors sharing one pair
of wires
On power-up, the SBE 38 reads its EEPROM, which includes calibration
coefficients and other setup information. As programmed, the SBE 38 samples
and transmits temperature continuously, or waits for a command to begin
sampling. Note that for RS-485 applications with several sensors sharing one
pair of wires, the SBE 38 cannot sample continuously.
The SBE 38 is frequently integrated as a remote temperature sensor with one
of our thermosalinograph instruments (SBE 21 Thermosalinograph or SBE 45
MicroTSG), to provide accurate sea surface temperature. See the manuals for
those instruments for integration information.
The SBE 38 is supplied with a powerful Win 95/98/NT/2000/XP software
package, SEASOFT-Win32, which includes:
•SEATERM terminal program for easy communication.
•SEASAVE real-time data acquisition and SBE Data Processing
post-processing programs – When the SBE 38 is integrated with the
SBE 21 or 45 thermosalinograph, SEASAVE and SBE Data Processing
can be used to view and process the entire data stream, including data
from the SBE 38.
Notes:
•Sea-Bird also supplies a DOS
software package, SEASOFT-DOS,
which can be used with the SBE 38.
However, this manual only details
use of the Windows software with
the SBE 38.
•Help files provide detailed
information on the use of
SEATERM, SEASAVE, and SBE
Data Processing.
•Separate software manuals on
CD-ROM contain detailed
information on the setup and use of
SEASAVE, SBE Data Processing,
and SEASOFT-DOS.
