NBL-RDO-206 Online Fluorescence Dissolved Oxygen Sensor

NBL-RDO-206 integrated on-line fluorescence dissolved oxygen sensor is designed and fabricated based on the quenching principle of excited fluorescence by specific substances in physics. When the excitation light is shone on the fluorescent material on the surface of the fluorescent film head, the fluorescent material is excited and emits fluorescence. The quenching time of fluorescence is affected by the concentration of oxygen molecules on the surface of the fluorescent film head.By detecting the phase difference between fluorescence and excitation light and comparing with the internal calibration curve, the concentration of oxygen molecules can be calculated, and the final value can be output after temperature and salinity compensation. No electrolyte is required and will not be polarized. No oxygen consumption, not affected by flow rate. Built-in temperature sensor, automatic temperature compensation. Free from interference by chemicals such as sulfides Small drift, rapid reaction, more accurate measurement. Long service cycle, lower cost of use. Simple replacement of fluorescent cap. Rs-485 interface, Modbus/RTU protocol. Low power consumption, anti-interference.

NBL-RDO-206 Online Fluorescence Dissolved Oxygen Sensor Technical specifications

1、Operational Principle

NBL-RDO-206A integrated on-line fluorescence dissolved oxygen sensor is designed and fabricated based on the quenching principle of excited fluorescence by specific substances in physics. When the excitation light is shone on the fluorescent material on the surface of the fluorescent film head, the fluorescent material is excited and emits fluorescence. The quenching time of fluorescence is affected by the concentration of oxygen molecules on the surface of the fluorescent film head.By detecting the phase difference between fluorescence and excitation light and comparing with the internal calibration curve, the concentration of oxygen molecules can be calculated, and the final value can be output after temperature and salinity compensation.

No electrolyte is required and will not be polarized.

No oxygen consumption, not affected by flow rate.

Built-in temperature sensor, automatic temperature compensation.

Built-in salinity compensation, flexible parameter setting

Free from interference by chemicals such as sulfides

Small drift, rapid reaction, more accurate measurement.

Long service cycle, lower cost of use.

Simple replacement of fluorescent cap.

Rs-485 interface, Modbus/RTU protocol.

Low power consumption，anti-interference.

2、Installation and electrical connection

2.1.Install

The sensor shall be installed fixedly below the liquid level. The installation and use shall avoid collision or scraping against the surface of the fluorescent film head. The fluorescent film head part shall avoid being attached by the bottom sediment.Remove the rubber cover when use.

2.2.Electrical connection

Red wire-power cord（12～24V）

Black wire-ground wire（GND）

Blue Line-485A

White Line-485B

Check wiring sequence carefully before power on to avoid unnecessary losses caused by wiring errors.

Cable specification: Considering that the cable is immersed in water (including sea water) for a long time or exposed to the air, all the wiring points are required to do waterproof treatment, the user cable should has certain corrosion resistance. 

3、Maintenance 

3.1.Maintenance schedule and methodology

3.1.1Maintenance schedule

Different from the dissolved oxygen probe technology of electrochemical principle, the fluorescence dissolved oxygen probe does not consume oxygen and does not need to be cleaned frequently (except when it is used in viscous liquid).

 Note: The maintenance frequency in the above table is only recommended, and the maintenance personnel shall clean the sensor according to the actual use of the sensor; however, the replacement frequency of the fluorescent cap is recommended once a year.

3.1.2 Maintenance method

a) Sensor outer surface: clean the outer surface of the sensor with tap water, if there is still debris residue, wipe with wet soft cloth, for some stubborn dirt, you can add some household washing liquid to tap water to clean.

b) Surface of fluorescent film head: If there is dirt on the surface of fluorescent film head, please rinse with clean water or wipe gently with a soft cloth.Pay attention to the intensity of cleaning to avoid causing scratches in the measuring area and affecting the measurement accuracy.

c) Inside the fluorescent film head: it is generally unnecessary to clean. If water vapor or dust enters into the fluorescent film head, the cleaning steps are as follows:

Screw down the fluorescent film head;

Rinse the inner surface of the fluorescent film head and the optical window of the sensor.

For oily dirt, you can use household cleaning solution;

Gently dry the water with a clean flannelless cloth and let dry;

4. Reinstall the fluorescent film head.

d) Check the cables of the sensor: there should be no damage to the skin and root of the cables;Terminals should not be submerged in water;When the sensor is normally installed, the cable should not be tensioned, otherwise the internal wire of the cable will easily break and the sensor cannot work normally.

e) Check whether the casing of the sensor is damaged by corrosion or other causes.

f) Daily storage of fluorescent film head: When not in use, a rubber protective cover with a wet sponge should be covered to keep the surface of the measuring area of fluorescent film head wet.If the surface of the measuring area of the sensor fluorescent film head is chronically dry, measurement error or data instability will occur, and it shall be soaked in water for 48 hours before use.

NBL-RDO-206 Online Fluorescence Dissolved Oxygen Sensor Data Sheet

NBL-RDO-206 Online Fluorescence Dissolved Oxygen Sensor.pdf