ESKO12 - optical dissolved oxygen sensor

Examples of use

Operational optical oximeter M2001-EKO is designed for continuous measurement of dissolved oxygen in many areas of water management:

  • Wastewater treatment plants
  • Technological processes in industrial production
  • Monitoring the water quality of streams and rivers
  • Fishing

Závěsný snímač rozpuštěného kyslíku ESKO12-Z

  • Accurate measurement without the need for regular calibration
  • It does not consume oxygen during the measurement andtherefore does not require flow around the sensor
  • Adjustable bracket adapted for quick installation of the rod sensor in the correct position
  • 10 m long cable at the hanging sensor
  • RS485 sensor communication interface under Modbus RTU protocol compatible with M4016 and M2001E units
  • Internal temperature sensor for measuring water temperature
  • Supply voltage in a wide range from 10 to 24V DC

Tyčový snímač rozpuštěného kyslíku ESKO12Principle of optical measurement of dissolved oxygen

The ESKO12 sensor works on the principle of measuring the intensity of radiation on the luminescent layer of the measuring head of the sensor caused by a short light pulse of high energy generated by the electronics of the sensor. Oxygen atoms absorb the energy of the pulse, which would otherwise be emitted in the form of photons by the phosphor atoms, and therefore the concentration of dissolved oxygen in the measured solution is inversely proportional to the measured intensity of the luminescent radiation.

The sensor also regularly measures the intensity from the phosphor of the reflected light of low energy (it does not cause luminescence) and uses this measured value during the actual autocalibration of the sensor.

Unlike Clark-type electrochemical sensors, optical sensors do not require regular calibrations, do not need to change electrolyte or clean the chemically worn anode, and last but not least, do not require solution flow around the measuring head because they do not consume any oxygen atoms in the measurement.

Characteristic properties

  • Robust mechanical design of the ESKO12 rod sensor - stainless steel tube with a diameter of 40 mm and a length of 1750 mm (500 snímače 4000 mm long on request).
  • ESKO12 dissolved oxygen sensor with DE2 holder The suspended version of the ESKO12-Z sensor is adapted for hanging the sensor on the supplied 10 m long cable. The cable is terminated with a 5-pin M12 connector with IP67 protection.
  • The sensors are placed in the measured medium at an inclination (30 to 45 degrees) to prevent the accumulation of gases on the surface of the luminescent measuring head (the inclination prevents the formation of an air pocket at the phosphor).
  • The luminescent method of measurement does not consume oxygen during the measurement and therefore the sensor does not require the flow of the measured medium around the measuring head.
  • Unlike the commonly used Clark electrochemical sensors, the optical sensor does not need to change the electrolyte and there is no gradual decay of the anode due to ongoing chemical reactions.
  • The sensor does not require calibration by the user (automatic autocalibration takes place during each measurement). It is recommended to verify the accuracy of the measured value only once a year with another reliable oximeter and to set a possible correction in the connected recording unit.
  • After 2-3 years of operation, the phosphor in the replaceable measuring head may be depleted. By fitting a new measuring head, the correct function of the sensor is restored.

Výměna hlavice snímače ESKO12

Connection of several sensors to one control unit

The adjustable sensor address allows up to 12 ESKO12 sensors to be connected to one RS485 bus. As standard, a 3 m long connection cable is supplied with the sensor, terminated on one side with a connector with high IP67 protection. The length of the connecting cable can be extended up to 500 m.


Detail of the connector connection of the ESKO12 rod sensor:

Detail konektorového připojení snímače ESKO12


Connection of pins of the ESKO12 rod sensor connector:

Hanging sensor ESKO12-Z:


Dimensions of the ESKO12-Z pendant sensor:

Rozměry snímače ESKO12-Z


Basic technical parameters

Measuring methodoptical measurement of excited luminescence
Measuring range0,00 to 20,00 mg/l
Measurement accuracy+/-0,1mg/l
Response speedreaching 90% of the value in <60 sec
Measurement frequencymin 1 measurement / sec
Working temperature range-10 to +60 °C
Maximum working pressure5 bar
Dimensions ESKO12 (diameter x length)40 x 1750 mm
Sensor materialnerezová ocel, Tecaform
Diameter of the phosphor of the measuring head10 mm
Weight of rod sensor ESKO122200 g
Weight of the ESKO12-Z pendant sensor1150 g
Sensor cable length ESKO12-Z10 m, conenctor M12
Power voltage12 to 24 V DC
InterfaceRS485, protocol Modbus RTU
Temperature compensationinternal NTC
Price list