idronaut Ocean Seven 310 - Physical Characteristics; The Standard Sensors; Lifetime and How to Replace the Idronaut Sensors; The Pressure Sensor

SECTION ONE – SYSTEM DESCRIPTION
IDRONAUT – Brugherio (MB) OCEAN SEVEN 310 CTD 01-2019
7
1.14 PHYSICAL CHARACTERISTICS
Housings:
1000 dbar
1500 dbar
2000 dbar
6000 dbar
7000 dbar
7000 dbar
(AISI316)
(POM)
(POM)
(Titanium)
(Titanium)
(Titanium)
Dimensions:
diameter
48 mm
100 mm
75 mm
48 mm
75 mm
89 mm
length
715 mm
710 mm
660 mm
660 mm
630 mm
720 mm
Weight:
in air
1.3 Kg
4.2 kg
3.3 Kg
2.1 Kg
5.0 Kg
8.0 Kg
in water
0.7 kg
0.2 Kg
1.7 kg
1.3 Kg
3.8 Kg
4.3 Kg
1.15 THE STANDARD SENSORS
This section provides a detailed presentation of the OCEAN SEVEN sensors.
1.15.1 LIFETIME AND HOW TO REPLACE THE IDRONAUT SENSORS
The IDRONAUT sensors are all pressure compensated and, in particular, the physical sensors (pressure,
temperature and conductivity) can last many years, if properly used. They are high-quality sensors, as
they are well known by oceanographers to measure salinity with great accuracy.
If thoroughly maintained by their respective hydrating caps and solutions, the IDRONAUT pH and
reference sensors can last several years. The sensor replacement requires that the closure screws on the
top head of the probe be unscrewed with a common screwdriver and the cylindrical housing be
removed (this takes very few minutes). The wire sensors are tin soldered on their respective connection
points placed on the printed circuit board. All sensor heads have a standard 12 mm diameter and are
provided with two O-rings (Parker 12-2) for sealing. This means that every sensor can be fitted in any
of the five sensor head holes. The pressure sensor is a high-quality transducer, which lasts many years
if properly used. Its replacement is not very easy and, moreover, it requires a Dead Weight Tester
System to obtain the factory calibration accuracy of 0.05% full scale.
1.15.2 The pressure sensor
The pressure sensor is a high quality strain gauge, centrally mounted on the probe base, capable of
generating a linear signal output, thus giving a resolution of 0.03% over the whole measuring range of
0 - 10000 dbar
Type: strain gauge
Measurement range: 0...10000 dbar
Accuracy: 0.05%FS
Resolution 0.002%FS
Response time: 50 ms @1 m/s
Measurement bridge resistance: @ 25°C Ω 3500 ± 20%
Excitation current: 0.6 mA
Insulation: @ 50 VCC MΩ 100
Operating temperature: °C -30…100
Sensor body: AISI 316L
Compensation: automatic compensation for temperature variations; not
compensated for the barometric pressure variations.
Life: unlimited.
Calibration frequency: monthly.
Maintenance: offset calibration in air.