The OCEAN SEVEN 304 CTD probe, completes the line of high quality and accuracy
IDRONAUT OCEAN SEVEN CTDs, fulfilling the demand for a high performance CTD
probe with very small diameter and extremely low power consumption. This CTD
probe can be easily integrated/adapted to third-party systems like floating
profilers and/or buoy-moored systems. The 304 CTD can, upon request, be
equipped with a wide range of interfaces like: RS232C, Asynchronous TTL
(0..5VDC), RS422.
Idronaut prides itself on the design of its pressure balanced full ocean
depth, pump free, low maintenance sensors. Central to which, is their well
known high accuracy seven-platinum-ring quartz conductivity cell, which can be
cleaned in the field without need of re-calibration. This unique quartz cell
employs a large diameter (8 mm) and a short length (46 mm) to guarantee
self-flushing and no clogging after long-term deployment even in biologically
active waters. Competitors' cells, which present few mm only of cell orifice
and very long cell length, are prone to clog even if protected by poisonous
antifouling devices. The OCEAN SEVEN 304 CTD does not require pumps or
other external devices to flush the sensors, which could further limit its
power consumption.
The 304 CTD offers a combination of 16-bit high resolution data accuracy, with
long-term sensor stability, making this CTD an ideal choice for both on-line
profiling and self-recording moored applications. The CTD uses
state-of-the-art electronics and is equipped with a 64-Mbyte logging memory,
acquiring and storing data in memory, according to customer defined
measurement schedules (see below).
Moreover, the user can select the proper conductivity range: for salt or fresh
water, making this CTD a very advanced tool for sampling sites near shore
influenced by fresh water inlets, or/and for borehole monitoring applications
SAMPLING MODES User selectable sampling/operating modes
include:
Continuous:
Sampling at fixed rates starting from 0.1 Hz to 8 Hz. Sampling
continues until interrupted. Multiple sessions are possible,
switching the CTD ON and OFF.
Pressure:
Data is sampled at regular pressure intervals. Multiple profiles can
be obtained switching the CTD ON and OFF. Two different methods
(conductivity/pressure) can be used to interrupt acquisitions when
the CTD returns to the surface. This data acquisition method is
ideal for profiling.
Timed:
CTD collects a series of samples, then sleeps for the configured
interval time before waking up again and repeating the acquisitions.
Time interval can be configured from 2 s up to 1 day. Battery power
is conserved while in sleep mode. This data acquisition method is
ideal for long-term monitoring.
Conditioned:
Data is sampled at fixed rates starting when the selected parameter
overcomes the configured boundary. Sampling continues until the
selected parameter falls below the configured boundary. Parameters
used to condition the sampling can be: Pressure, Temperature and
Conductivity. Whenever the acquisition cycle starts, the CTD uses
the same rules of the "Continuous" data acquisition. Monitoring of
the selected parameter occurs at the configured interval.
REAL-TIME
COMMUNICATIONS
The OCEAN SEVEN 304 CTD communicates with a computer via a standard
RS232C interface. Real-time data can be acquired by means of the
REDAS Windows software. An optional RS422 interface overcomes the
limitation of the RS232C cable maximum length (100 m) and allows the
probe to transmit data through distances up to 1000 m. The
communication speed is user selectable among: 9600, 19200, 38400 and
57600 bps.
SOFTWARE
A programme operating under Windows 98se/ME/2000/XP allows the
operator to configure the OCEAN SEEVN 304 CTD data acquisition and
logger functions and upload data from the 64-MByte internal memory.
The software package comprises:
ITERM:
terminal emulation programme to easily communicate with the OCEAN
SEVEN 304 CTD using the probe integrated operator interface.
REDAS:
data processing and retrieval programme which allows the display and
plotting of conductivity, temperature, pressure and derived
variables such as salinity, sound speed, density, according to
UNESCO formulas and recommendations.
DATA STORAGE AND
BATTERY ENDURANCE
The OCEAN SEVEN 304 CTD allows the storing of 2,006,048 data sets
each one being composed of the reading of: conductivity, temperature
and pressure sensors plus the acquisition date and time. The 304 CTD
is powered by two PP3 9V alkaline batteries connected in parallel
which provide 1 A/h sufficient to keep the CTD continuously ON for
36 hours in continuous sampling mode and at the maximum sampling
rate.Further battery endurance can be obtained by using three 6V
lithium batteries (instead of the two 9V alkaline type) which
increase the battery endurance up to 190 hours of continuous
operation. Whenever the CTD operates in "Timed Mode", the battery
endurance can be considerably extended because the CTD waits for the
interval between acquisitions in "Sleep mode".
The OCEAN SEVEN 304 CTD can be equipped with the following sensors to
measure:
up to 8 Hz (depending on the
probe sampling method).
Interfaces
RS232C, Asynchronous TTL
(0..5VDC), RS422.
Baud Rate
up to 57600 bps (9600 bps
default).
Data memory
64 MBytes
A/D converter
16-bit successive approximation
Analogue input
4 multiplexed analogue inputs.
Supply Voltage
4.5..11 V, nominal 9 V.
Running:
Sleep:
23 mA@9V.
0.045 mA@9V.
Communication protocol
Operator interface
Batteries
proprietary byte oriented binary and plain
message protocol.
friendly menu driven user interface.
Two 9V, 0.5 A/h, PP3 alkaline batteries assembled in parallel, or three 6V
lithium batteries.
PHYSICAL CHARACTERISTICS
Housing: AISI 316
1000 dbar (AISI 316/black POM)
6000 dbar (AISI 316)
Dimensions:
housing diameter
43 mm(*)
48 mm
total length
515 mm
515 mm
Weight:
in air
1.3 kg
3.1 kg
in water
0.7 kg
2.3kg
(*) The removable titanium sensor protection presents a
diameter of 44 mm.
OEM versions of the OCEAN SEVEN 304 CTD electronics and sensors are available
upon request.
