Manual revision 041
Section 2: Description of MicroCAT
SBE 37-SM RS-232
11
Specifications
Temperature (°C)
Conductivity
(S/m)
Optional
Pressure
Measurement
Range
-5 to +45
0 to 7
(0 to 70 mS/cm)
0 to full scale range:
20 / 100 / 350 / 600 /
1000 / 2000 / 3500 /
7000 meters
Initial
Accuracy
± 0.002
(-5 to 35 °C)
;
± 0.01
(35 to 45 °C)
±
0.0003
(0.003 mS/cm)
±
0.1% of
full scale range
Typical
Stability
0.0002
per month
0.0003
(0.003 mS/cm)
per month
0.05% of
full scale range
per year
Resolution
0.0001
0.00001
(0.0001 mS/cm)
0.002% of
full scale range
Sensor
Calibration
+1 to +32
0 to 6;
physical calibration
over range 2.6 to 6 S/m, plus
zero conductivity (air)
Ambient pressure to
full scale range in
5 steps
Memory
8 Mbyte non-volatile FLASH memory
Data
Storage
Conductivity & temperature: 6 bytes per sample (3 bytes each)
Time: 4 bytes per sample.
Pressure (optional): 5 bytes per sample.
Recorded Parameters
Memory Space (number of samples)
C, T, and time
800,000
C, T, P, and time
533,000
Real-Time Clock
32,768 Hz TCXO accurate to
1 minute/year.
Battery Pack
Nominal 7.8 Amp-hour pack consisting of 12 AA Saft LS 14500
lithium cells (3.6 V and 2.45 Amp-hours each), with 3 strings of 4
cells. For battery pack endurance calculations, derated capacity of
257 KJoules (see
Battery Pack Endurance
for example calculation).
See
Shipping Precautions
in
Section 1: Introduction
.
Note: Saft cells can be purchased from Sea-Bird or other sources.
See Saft’s website for suppliers (www.saftbatteries.com).
Alternatively, substitute either of the following:
- Tadiran TL-4903, AA (3.6 V and 2.4 Amp-hours each)
(www.tadiran.com)
- Electrochem 3B0064/BCX85, AA (3.9 V and 2.0 Amp-hours each)
(www.electrochemsolutions.com)
External
Input Power
0.25 Amps at 9-24 VDC. To avoid draining internal battery pack, use
external voltage greater than 10 VDC. See
External Power
.
Power
Requirements
Quiescent current: 30 microAmps (0.0004 Watts).
Communication current: 4.3 milliAmps.
Acquisition current:
- 9.1 milliAmps if transmitting real-time data.
- 7.9 milliAmps if not transmitting real-time data.
Acquisition time: 1.9
– 2.9 seconds per sample (depending on
sampling mode and inclusion of pressure sensor, see
Sample
Timing
).
Housing and
Depth Rating
Titanium housing, 7000 m (23,000 ft)
Plastic housing, 350 m (1150 ft)
Weight
(without pressure
sensor)
Titanium housing:
In air: 3.3 kg (7.2 lbs) In water: 2.0 kg (4.3 lbs)
Plastic housing:
In air: 2.4 kg (5.2 lbs) In water: 1.1 kg (2.3 lbs)
Note:
Pressure ranges are expressed
in meters of deployment depth
capability.
CAUTION:
See
Section 5: Routine
Maintenance and Calibration
for
handling instructions for the
plastic
ShallowCAT
housing.
