OCEAN SEVEN 28 Compact-Lightweight CTD


The OS 28 CTD has been designed as light-weight payload that can be easily integrated into autonomous vehicles such as AUVs, SAVs and ROVs.
The OS28 can operate autonomously, in self-recording mode or communicate in real-time with the vehicle on-board processing units.
Due to the very small diameter (Ø 28mm), the OS 28 can also be used for borehole monitoring.

The OCEAN SEVEN 28 CTD represents a real breakthrough in the concept of miniaturization, integration and performance.
The adoption of a new generation of electronic devices, the OS 28 CTD can guarantee sampling rates up to 20Hz without degradation of the measurement performance.
IDRONAUT prides itself on the design of pump free, low maintenance sensors.
The OS 28 CTD does not require pumps or any other external device to flush the sensors, which minimizes its power consumption.
The OS 28 CTD is characterized by drift free sensor preamplifiers.

    The OS28 can deliver real time data to the interfaced autonomous vehicle’s data processing unit through the built-in RS232/USB-C interface using a plain ASCII protocol with a user configurable rate from 2Hz up to 20Hz. The data transmission format can be easily customized on request to meet the vehicles data input requirements. The internal power supply is galvanically isolated and can utilise external power from 7 to 30V DC and guarantees an interference free installation. A MCBH-6-MP bulkhead connector is installed on the top cover.
    The high accuracy seven-platinum-ring quartz conductivity cell (patented) can be cleaned in the field without the need for re-calibration. This unique quartz cell employs a large diameter (8mm) and a short length (46mm) to guarantee self-flushing and no fouling after long-term deployment even in biologically active waters.
    The OS 28 CTD conductivity sensor calibration can be checked in field by immersing the CTD in a container of IAPSO sea water standard. Afterwards, and if required, the conductivity sensor calibration can be adjusted by means of a dedicated software calibration function.

The OS 28 CTD is equipped with a 4-Gbyte SD memory card, which allows the storing of about 60M data sets, each one being composed of the reading of the CTD sensors plus the acquisition date and time. USB high speed interface reduces data uploading time. Inside the OS 28 CTD housing is installed a “AA” Li-SOCI2 Lithium non-rechargeable battery (3.6V, 2.4 Ah). A rechargeable 3.6V “AA” lithium battery can be optionally installed.



OS 28 CTD battery and data storage autonomy calculated according different sampling rate and time intervals.

The OS28 multiparameter CTD can be equipped with the following sensors to measure:

(1) At 1 m/second flow rate.
Derived parameters such as: Salinity, Sound Speed, Water Density, Oxygen ppm are obtained using the algorithms described in the UNESCO “Technical papers in marine science no.44 – Algorithms for computation of fundamental properties of sea water”.