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Online Conductivity (Salinity), Temperature and Depth Sensor

Mini CTD salinity sensor for connection to embedded systems

Conductivity (CTD) sensor connection port for subsea device integration. For both short or long-term oceanographic surveys.

Key features

  • Smallest online conductivity sensor on the market
  • Real time data streaming or data retrieval after surveying
  • Fully submersible rugged design
  • Pressure sensors from shallow to deep ocean
  • Description

    Smallest CTD on the market

    The small and handy CTD online is a modified version of the popular DST CTD standalone data logger. The sensor probe is only 22 mm in diameter and 75 mm in length and a subsea cable connects to the connector end. The small measuring device is also available as a CT online if depth measurements are not required.


    The online CTD sensor is used for hydrographic and oceaonographic studies:

    • Survey missions where it is a part of autonomous underwater vehicles (AUV), either streaming data in real-time or for later data retrieval when AUV is surfaced.  
    • Long term stationary monitoring underwater where it is connected to a data logging system.
    • For using the CTD without wired connection, as a self-contained logger, click here.

    Fully submersible rugged design

    The housing is ruggedly designed for durability, strong breakage resistance and high pressure survival. The CTD online has a robust plastic molding around the ceramic sensor housing and the housing has a threaded steel connector on the end. The subsea cable comes with a matching subsea connector for a quick and easy connection to the CTD. 

    Depth sensors from shallow to deep ocean

    Customers choose between depth calibration ranges up to 100 m, 500 m, 1200 m or 2400 m. The shallower the range the better the depth resolution and accuracy.

    Originally designed for NASA

    The online CTD was initially designed for use on NASA‘s micro-sub deployed in waters deep under the Antarctic glacier, exploring lifeforms deep under the glacier. Star-Oddi's CTD logger was chosen by NASA because of its small size and reliability.