M2001-EKO for optical measurement of dissolved oxygen

Optical sensor ESKO12

• Luminescent optical method for measuring the concentration of dissolved oxygen

• Accurate measurement without the need for regular calibration

• It does not consume oxygen during the measurement and therefore 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

M2001E display unit

• Display of dissolved oxygen value and water temperature

• 3 programmable relays for blower control and alarms

• 2 galvanically isolated active output signals 4-20 mA

• Recording of measured values and statistics (min, max, ...)

Application

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

Basic description

The set for optical measurement of dissolved oxygen consists of a separate ESKO12 sensor and an M2001E display unit. Both devices are interconnected by a cable terminated by a detachable connector, after which the ESKO12 sensor from the M2001E unit is powered and after which there is also a mutual digital communication between the devices via the RS485 bus under the Modbus RTU protocol.

ESKO12 sensors can also be connected directly to the control and recording unit type M4016.

As an optional accessory, a universal DE2 holder is usually included in the delivery of the rod sensor, which allows this sensor to be installed at an inclination important for correct measurement.

Principle 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.

Characteristics of the ESKO12 optical sensor

• 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.

Characteristics of the M2001E display unit

Clear and understandable MENU together with a large number of adjustable parameters allow to optimize the measurement with regard to the needs of connected devices (dosing pumps, single or two-speed blowers, frequency converters). Parameters include, for example, damping of fast changes of the measured quantity or limits and hysteresis of own and external relays. The M2001E calibration unit can control 3 own and up to 12 external relays in the DV2 or DV3 switching units.

Automatic cleaning of the electrode (sensor) can be performed with the help of the programmable time relay "Rinses". The last measured value remains fixed at the current output during the rinsing time and during the calibration or recalibration.

One of the relays itself can be set as the output of the PI controller. The controller constants are set from the MOST program via RS232.
The plug-in module of the second 4-20 mA current output can be used for temperature transfer or as another output of the measured quantity.

A KR1 stainless steel cover can be ordered for the M2001E outdoors.

M2001E terminal connection:

Connecting the connection cable for the M2001E:

Dimensions of the ESKO12-Z pendant sensor:

Documentation: 

Datasheet

ESKO12-V2

Download: 

Datasheet

Devices for water service

Price list

Price List 2024