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In-Line Optical Dissolved Oxygen Transmitter

inline or in-flow optical dissolved oxygen transmitter OD8525

The OD8525 is a dissolved oxygen sensor designed for mounting inline or in the flow of pipework. The OD8525 has integrated electronics to provide an industry standard 4-20mA output, corresponding to the concentration of dissolved oxygen or the percentage saturation.

4-20mA Inline Dissolved Oxygen Transmitter

The OD8525 is a fluorescent optical dissolved oxygen transmitter.  Using a specially coated fluorescent layer, we can accurately measure the dissolved oxygen content of a solution by the way in which it interacts with various wavelengths of light.

The measured dissolved oxygen is not consumed by using this method (unlike with Polarographic or Clarke type Sensors) and it is not dependant upon a constant flow of solution.

The instrument is designed to IP68 specification with mounting flange for the OD8525 to be held in place in the inline holder. This allows the OD8525 to continuously measure the dissolved oxygen concentration or saturation in a flow line application.

The 4-20mA output signal from the OD8525 is isolated to 600Ω and is suitable for directly connecting to PLC, online Data Logger, digital Chart Recorder or a 4-20mA controller, such as our BC7635.

As a loop powered device, the OD8525 is powered from the same 2 wires that also send out the 4-20mA signal to the receiving device.  This makes the OD8525 incredibly simple to ingrate with PLC's and other control equipment.

Optical Dissolved Oxygen Measuring Ranges

The OD8525 is able to measure the following parameters:-

  • Dissolved Oxygen Saturation with range 0-200.0%
  • Dissolved Oxygen Concentration with range  0-20.00 ppm

Using integrated temperature measuring devices, the OD8525 automatically compensates for temperature when providing the 4-20mA output signal.

Using a personal computer with a hyper-terminal client, the user can interrogate the OD8525 and set secondary environmental parameters to compensate to the dissolved oxygen measurement. The secondary parameters are as follows:-

  • Pressure (mmHg) with range 500-800 mmHg
  • Salinity (Chloride) in ppm with range 0-60'000 ppm
  • Relative Humidity (%) with range 0-100%

Using the hyper-terminal client, the zero point and sensitivity can be adjusted, as well as the output 4-20mA current signal.

We can adjust any of the settings or output measuring range at the factory, prior to the OD8525 being despatched.

Inline or inflow Dissolved Oxygen Transmitter

The OD8525 is designed to be mounted into pipework using a locking assembly.  When secured into place, the OD8525 is designed to provide a continuous 4-20mA output, corresponding to the percentage saturation of dissolved oxygen or the dissolved oxygen concentration.  The OD8525 is manufactured in PVC and can operate up to 6 Bar pressure.

Inline or Inflow Dissolved Oxygen Transmitter Applications

The OD8525 is incredibly simple to install and to integrate with measurement and control equipment.  The OD8525 fluorescent technology provides a relatively maintenance free operation and offers exceptionally accurate dissolved oxygen measurements, even when low levels of dissolved oxygen concentration or saturation are present.

The precision at very low levels of dissolved oxygen means that the OD8525 is perfect for mounting on incoming boiler feed water lines, particularly as dissolved oxygen can cause significant damage to boilers in process applications.  The OD8525 is often used in recirculating lines for aquaculture, as well as being particularly suitable within the leisure sector.  With the ability to make adjustments for relative humidity and salinity in a controlled environment, it is also often used in the exotic aquaculture sector.

OD8525 Features and Benefits

The OD8525 is a precision dissolved oxygen sensor for semi-permanent mounting into pipework, or for inline or inflow mounting.

It provides a continuous dissolved oxygen measurement with an isolated 4-20mA output signal which is proportional to either the percentage saturation of dissolved oxygen, or the concentration of dissolved oxygen in ppm.

The OD8525 uses the fluorescent principle of measuring dissolved oxygen.  This offers significant advantages over the polarographic membrane or Clarke type sensors.  Most notably, the dissolved oxygen is not consumed as it is measured, and a constant flow rate is not required to provide an accurate measurement.

The OD8525 is manufactured in PVC and is suitable for a maximum pressure of 6 Bar.  It is powered from the same two wires that receive the 4-20mA current signal.

OD8525 Submersible Dissolved Oxygen Transmitter Specifications

  • Specifications


    Inline Optical Fluorescent Dissolved Oxygen Transmitter

    Model No:- OD8525

    Dissolved Oxygen Satuation Range:- 0-200.0%

    Dissolved Oxygen Saturation Resolution:- 0.1%

    Dissolved Oxygen Concentration Range:- 0-20.00 mg/L

    Dissolved Oxygen Concentration Resolution:- 0.01 mg/L

    Temperature Compensation Range:- 0.0-50.0°C

    Temperature Resolution:- 0.1°C

    Dissolved Oxygen Auto Temp Comp (ATC):- Via Automatic Lookup Table

    Repeatability Dissolved Oxygen:- ±0.5% of Dissolved Oxygen Scale

    Dissovled Oxygen Response Time:- 95% : < 60 seconds

    Operating temperature:- 0-50ºC

    Operating Pressure:- 10 Bar

    Power supply:- 9 / 36 VDC

    Weight:- 800 grams

  • Features


    • Inline Dissolved Oxygen Sensor for installation into pipework for measuring inline or in flow dissolved oxygen levels.
    • Optical Fluorescent type dissolved oxygen sensor - dissolved oxygen is not consumed by the measuring device and a constant flow rate is not required for accurate DO2 measurements.
    • Simple to install and connect to measurement and control equipment - the 4-20mA current output is loop powered, meaning that the same two wires that transmit the signal also transmit the measurement signal.
    • The OD8525 has no moving parts and requires minimal periodic calibration and maintenance.
    • Factory set or configurable via computer - the OD8525 can be set with barometric pressure measurements, salinity measurements and relative humidity for precision readings even in challenging environmental conditions.
    • The OD8525 is designed for a number of inprocess applications - including boiler feed water and in marine applications.
  • Data Sheets

    Data Sheets


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