User`s manual

Manual revision 016 Section 2: Description of FastCAT SBE 49
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Section 2: Description of FastCAT
This section describes the functions and features of the SBE 49 FastCAT,
including specifications, dimensions, connector, and communications.
System Description
The SBE 49 FastCAT is an integrated CTD sensor intended for towed vehicle,
ROV, AUV, or other autonomous profiling applications in marine or fresh-
water environments at depths up to 350 meters (1150 feet) or 7000 meters
(22,900 feet). The FastCAT’s pump-controlled, TC-ducted flow minimizes
salinity spiking, and its 16 Hz sampling provides very high spatial resolution
of oceanographic structures and gradients.
The FastCAT’s temperature thermistor and conductivity cell are the same as
used in our premium 911plus CTD system. The strain-gauge pressure sensor is
offered in eight full scale ranges from 20 to 7000 dbars. Sophisticated
interface circuitry provides very high resolution and accuracy — entirely
comparable to the 911plus.
The FastCAT is an easy-to-use, light, and compact instrument ruggedly made
of titanium and other low-maintenance (plastic) materials; it is well suited to
even the smallest vehicle. There are straightforward commands for continuous
(full rate or averaged) or single sample acquisition. EEPROM-stored
calibration coefficients permit data output in ASCII engineering units
(degrees C, Siemens/m, decibars, Salinity [PSU], and sound velocity [m/sec]),
or the user can select raw data output if desired.
The FastCAT is externally powered, and its data is telemetered by its RS-232C
interface. The FastCAT has no memory or internal batteries, and does not
support auxiliary sensor inputs.
The FastCAT samples in two modes:
• Autonomous sampling –The FastCAT runs continuously, sampling at
sixteen scans per second (16 Hz). It can be set to average up to
255 samples, transmitting only the averaged data. Programmable real-time
processing – aligning, filtering, and correcting data for conductivity cell
thermal mass effects – provides high quality data for applications where
post-processing is not feasible. The FastCAT can be programmed to begin
autonomous sampling when power is applied or on command.
• Polled sampling – On command, the FastCAT takes one sample and
transmits the data.
If deploying
vertically,
intended for
deployment
in orientation
shown
(sensors
at top) for
proper pump
operation
Intake
Exhaust