NBL-RDO-406-S Online Fluorescence Dissolved Oxygen Sensor: For Wastewater Treatment and Aquaculture Online Monitoring

NBL-RDO-406-S Online Fluorescence Dissolved Oxygen Sensor: A No-Consumption, High-Stability Industrial-grade Dissolved Oxygen Online Monitoring Solution

In wastewater treatment, industrial water treatment and aquaculture processes, dissolved oxygen (DO) concentration is a key process control parameter. Traditional electrochemical dissolved oxygen sensors are prone to polarization, require frequent electrolyte replacement, are greatly affected by flow rate and have high maintenance costs. The NiuBoL NBL-RDO-406-S online fluorescence dissolved oxygen sensor is based on the fluorescence quenching principle. It detects changes in fluorescence lifetime on the surface of the fluorescent membrane head, combined with temperature and salinity compensation, and outputs accurate dissolved oxygen concentration values in real time. The sensor does not consume oxygen, is not affected by flow rate, has strong chemical interference resistance, is easy to install and maintain, and is particularly suitable for system integrators and engineering contractors to build long-term stable and highly reliable online water quality monitoring systems, effectively solving the industry pain points of frequent maintenance, large drift and complex integration in traditional DO sensors.

Core Advantages

• Maintenance-Free and High Stability: No electrolyte required, no oxygen consumption, fluorescent membrane head life up to 1 year, small drift, fast response, accurate and reliable long-term measurement.

• Strong Anti-Interference and Precise Compensation: Built-in temperature sensor realizes automatic temperature compensation, supports salinity compensation parameter setting, and is not affected by chemical substances such as sulfides.

• Easy Integration and Reliable Protection: Natively supports RS-485 Modbus/RTU protocol, optional 4-20 mA output, IP68 protection rating, 316L stainless steel housing, suitable for harsh industrial environments.

NBL-RDO-406-S Online Fluorescence Dissolved Oxygen Sensor Product Overview

The NiuBoL NBL-RDO-406-S online fluorescence dissolved oxygen sensor is an integrated industrial-grade online dissolved oxygen monitoring device designed based on the physical fluorescence quenching principle. When excitation light illuminates the surface of the fluorescent membrane head, the fluorescent material is excited and emits fluorescence. Oxygen molecule concentration affects the fluorescence decay time. By detecting the phase difference between fluorescence and excitation light, comparing it with the internal calibration curve, and combining temperature and salinity compensation, the final dissolved oxygen concentration value is output.

The sensor requires no electrolyte or oxygen consumption, has fast response and small drift, significantly reducing maintenance costs and replacement frequency. For system integrators, the standardized Modbus protocol allows direct connection to PLC, DCS or IoT platforms for seamless data collection and remote monitoring. For engineering contractors, it greatly simplifies on-site installation and long-term operation and maintenance work, ensuring the monitoring system operates stably under complex water quality conditions. The product has undergone 72-hour aging testing and strict quality inspection, and has high reliability upon leaving the factory.

NBL-RDO-406-S Online Fluorescence Dissolved Oxygen Sensor Key Technical Advantages

1. Advanced Fluorescence Quenching Measurement Technology
   The sensor adopts the fluorescence method principle, does not consume oxygen, is not affected by water flow velocity, and provides more accurate measurement. The built-in Pt1000 temperature sensor realizes automatic temperature compensation, and simultaneously supports flexible setting of salinity compensation parameters to ensure high precision in water bodies with different salinities. The fluorescent membrane head is insensitive to common chemical substances such as sulfides, has strong anti-interference ability, small drift and rapid response.

2. Rugged and Durable Hardware Design
   - Housing material is 316L stainless steel, with excellent corrosion resistance, suitable for industrial wastewater, seawater and various corrosive media.
   - Protection rating IP68, can work stably submerged underwater for a long time.
   - The fluorescent membrane head is designed as an easy-to-replace structure with a normal service life of 1 year, significantly reducing long-term use costs.
   - Installation method is submerged, and on-site fixed installation is simple and convenient.

3. Intelligent Communication and Low Power Consumption Integration
   Supports RS-485 Modbus/RTU protocol, with stable and reliable communication, easy to seamlessly integrate with various host computer systems. Optional 4-20 mA analog output meets the needs of different control systems. Power consumption is only 0.2W@12V, and the low-energy design is suitable for distributed or remote monitoring stations. At the same time, anti-interference circuit design is adopted to ensure stable data transmission.

4. Convenient Maintenance and Calibration
   The fluorescent membrane head has low maintenance frequency and only requires routine cleaning every 30 days. The membrane head is replaced once a year. Two-point calibration method (zero point + slope). Zero point uses 5% sodium sulfite solution, and slope can be completed in air-saturated water or water-saturated air. Avoid air bubbles attaching to the fluorescent membrane head surface and mechanical damage to maintain long-term performance.

These technical features enable the NBL-RDO-406-S to operate stably for a long time in unattended environments and significantly improve the engineering reliability and economy of the entire dissolved oxygen monitoring system.

NBL-RDO-406-S Online Fluorescence Dissolved Oxygen Sensor Technical Specifications

Note: The sensor connector is M16-5-core waterproof male connector, and the cable is 5-core shielded wire.

NBL-RDO-406-S Online Fluorescence Dissolved Oxygen Sensor Application Scenarios

1. Municipal Wastewater Treatment Plants: Real-time monitoring of dissolved oxygen concentration in aeration tanks to optimize aeration volume, reduce energy consumption and ensure treatment effect.

2. Industrial Wastewater Treatment Systems: Suitable for wastewater treatment processes in chemical, pharmaceutical, food and other industries to precisely control dissolved oxygen and ensure biochemical treatment efficiency.

3. Aquaculture and Aquaculture Farms: Monitoring dissolved oxygen levels in aquaculture water bodies to prevent hypoxia risks and ensure healthy growth of cultured organisms.

4. Environmental Water Bodies and River/Lake Monitoring: Used for online dissolved oxygen monitoring in surface water and landscape water bodies to support water environment quality assessment.

5. Boiler Feed Water and Industrial Circulating Cooling Water: Monitoring dissolved oxygen content to prevent equipment corrosion and extend equipment service life.

6. Marine and Port Water Quality Monitoring: Combined with the corrosion resistance of 316L material, suitable for dissolved oxygen monitoring in seawater environments.

NBL-RDO-406-S Online Fluorescence Dissolved Oxygen Sensor Installation and Wiring Guide

Installation requirements: Use submerged installation and immerse the sensor below the liquid surface for fixation. During installation, avoid impacting or scratching the fluorescent membrane head surface to prevent sediment from attaching to the bottom of the membrane head. Remove the protective rubber cap before use.

Electrical Connection: Use 5-core shielded cable with the following wiring definition:

• Red wire: Power positive (12～24V DC)

• Black wire: Ground (GND)

• Blue wire: RS-485 A

• Green wire: RS-485 B

• Yellow wire: 4-20 mA current output (optional, leave floating if not in use)

Before powering on, please carefully check the wiring sequence. All wiring points must undergo waterproof treatment. User cables should have certain corrosion resistance. During normal installation, the cable should not be tensioned to prevent internal breakage.

FAQ

Q1: What are the main advantages of NBL-RDO-406-S compared with traditional electrochemical dissolved oxygen sensors?

A: Fluorescence sensors require no electrolyte, do not consume oxygen, are not affected by flow rate, have low maintenance frequency, longer service life, smaller long-term drift and lower overall use cost.

Q2: How often does the fluorescent membrane head need to be replaced?

A: Under normal use conditions, it is recommended to replace the fluorescent membrane head once a year. Daily routine cleaning is required only every 30 days.

Q3: Does the sensor support salinity compensation?

A: Yes. It has a built-in salinity compensation function. Users can flexibly set parameters according to actual water salinity to ensure measurement accuracy.

Q4: How to perform two-point calibration of the sensor?

A: Zero point calibration uses 5% sodium sulfite solution, and slope calibration can be completed in air-saturated water or water-saturated air. After the value stabilizes for 3 minutes, perform calibration through Modbus commands.

Q5: Will chemical substances such as sulfides interfere with measurement?

A: No. The fluorescence method principle is insensitive to common chemical interferents such as sulfides and can work stably in complex industrial wastewater.

Q6: What systems does the sensor support for integration?

A: Natively supports RS-485 Modbus/RTU protocol and can be directly connected to PLC, DCS, SCADA and IoT platforms. Optional 4-20 mA output meets the needs of analog control systems.

Q7: How to clean a dirty fluorescent membrane head surface?

A: Rinse with clean water or gently wipe with a soft cloth. Avoid scratching the measurement area. Internal cleaning is generally not required. If water or dust enters, disassemble and clean according to the instructions, dry and reinstall.

Q8: What about the product warranty and after-sales?

A: One-year warranty service is provided from the date of sale (excluding improper use). If there are installation, calibration or technical problems, please feel free to contact the NiuBoL technical support team at any time.

Summary and Cooperation Invitation

The NiuBoL NBL-RDO-406-S online fluorescence dissolved oxygen sensor provides a high-stability, low-maintenance-cost professional solution for industrial water quality dissolved oxygen online monitoring with fluorescence quenching principle as the core, relying on no oxygen consumption, strong anti-interference capability, automatic temperature and salinity compensation, and standardized Modbus communication protocol. It not only improves measurement accuracy and system reliability but also helps engineering projects significantly reduce long-term operation and maintenance investment.

If you are planning wastewater treatment upgrades, aquaculture intelligent transformation, industrial process water quality control or environmental online monitoring projects, please feel free to contact the NiuBoL technical team. We can provide detailed technical materials, integration solution consultation, on-site installation guidance and stable supply assurance. Contact us immediately to obtain the complete product manual or apply for prototype testing, and work with NiuBoL to build an efficient and reliable industrial IoT water quality monitoring system, making precise dissolved oxygen monitoring the solid guarantee of your engineering projects.

NBL-RDO-406-S Online Fluorescence Dissolved Oxygen Sensor Data Sheet

NBL-RDO-406-S Online Fluorescence Dissolved Oxygen Sensor.pdf