In-Situ RDO Pro-X

In-Situ RDO Pro-X

Item. no.: 5050424 (10 m cable)

Advantages at a glance

  • Patented RDO technology
  • No calibration required
  • Measurement extremely drift-stable
  • Full flexibility in terms of application and connection options

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In-Situ RDO Pro-X

In-Situ's oxygen probes use the market-leading and patented Rugged Dissolved Oxygen technology to optically measure dissolved O2 in gases and liquids. Approved by the EPA for Clean Water Act programs, this method uses no oxygen and works in stagnant water.


  • RDO probes require no calibration or conditioning prior to use and do not require membranes.  
  • The RDO Smart Sensor Cap can be replaced by the user after 2 years in just a few simple steps. The remaining operating time is displayed.
  • The factory calibration is stored on the cap and is carried out over 90 points of the entire temperature and measuring range. This makes the measurement extremely stable against drift.  
  • A unique three-layer system ensures unsurpassed resistance to chemicals and abrasion.

Areas of application

The low-maintenance and durable probes are suitable for hand-held use and long-term use in fresh or salt water, as well as for aquaculture applications and use in demanding environments in the waste water sector and for process control in industry.


The proven RDO Pro-X probe offers full flexibility in terms of application and connection options. It is available with a fixed cable or bayonet connection. Cable length and communication protocol are freely selectable (Modbus/RS-485, 4-20 mA, SDI-12), for connection to external loggers, telemetry devices and for integration into all SCADA/PLC systems. In addition to the VuLink in-well modem and the HydroVu cloud solution from In-Situ, we also offer data transmission for the RDO Pro-X probe with our NB-IoT Box as a variant for remote data transmission, including SVADSS data portal and management on request.  

The new RDO Bluehas been optimized as a low-cost probe for use in aquaculture systems. The temperature sensor is installed internally and the entire probe and cable connection are fully encapsulated, making the probe even more durable and robust. The RDO Blue is available with Modbus/RS-485 protocol and cable lengths.  

Both probes can be fitted with either the RDO-X cap or the RDO fast cap. The Air-blast Adapter and the Antifouling Guard are available as accessories for protection against biofouling.

Measuring principle

The patented Rugged Dissolved Oxygen technology from In-Situ measures the dissolved oxygen content optically using the principle of luminescence quenching. Light pulses are directed onto the sensor foil and excite the lumipore molecules. The excited Lumiphore molecules emit red light, which is detected by a photodiode. Oxygen molecules "quench" the excited molecules and prevent the emission of red light - a process known as "dynamic luminescence quenching". The rate at which this fluorescence decays is inversely proportional to the amount of oxygen present in the environment. This type of measurement is particularly linear over a wide measuring range and very drift-stable.

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