NBL-CDOM-406-S Colored Dissolved Organic Matter Sensor by Fluorescence Method: IoT Water Quality Monitoring

NBL-CDOM-406-S Online Colored Dissolved Organic Matter Sensor Product Overview

The NiuBoL NBL-CDOM-406-S online colored dissolved organic matter sensor is based on the fluorescence method principle. It utilizes the absorption and emission peak characteristics of colored dissolved organic matter (CDOM) in the spectrum, measures the fluorescence intensity after excitation by monochromatic light, and realizes real-time and continuous monitoring of CDOM concentration in water. The sensor integrates automatic temperature compensation and can simultaneously output concentration and temperature data, providing a reliable basis for water body organic pollution assessment.

The sensor is easy to install, has low maintenance requirements and stable performance. It is particularly suitable for deployment by system integrators and engineering contractors in environmental monitoring, drinking water source protection and industrial wastewater treatment projects. NiuBoL is committed to the research and development of industrial-grade optical water quality sensors. Through high-stability digital output, it helps users build real-time and reliable water environment monitoring systems to support water quality safety and ecological management.

NBL-CDOM-406-S Online Colored Dissolved Organic Matter Sensor Core Advantages

• Fluorescence High-precision Detection: Measurement range 0～2.000 mg/L, resolution 0.001 mg/L, accuracy ±3% (reading), response time T90＜30s, minimum detection limit 0.02 mg/L. Supports two-point calibration with high linearity, meeting the needs of precise organic matter monitoring.

• UV LED Light Source and Anti-interference Design: Uses high-stability UV LED light source with small drift and long service life. The AC drive method effectively filters natural light interference, ensuring stable and reliable measurement values in outdoor or changing light environments.

• Automatic Temperature Compensation and Protection Capability: Built-in Pt1000 automatic temperature compensation corrects the influence of temperature on fluorescence intensity. The 316L stainless steel housing has strong corrosion resistance, IP68 protection rating, supports long-term underwater immersion, operating conditions 0～50℃, ＜0.2 MPa, and is suitable for freshwater, seawater and industrial water bodies.

• Low Power Consumption and Easy Integration: Power consumption is only 0.2W@12V. The low-energy feature is suitable for solar-powered or remote monitoring stations. Standard RS-485 interface follows Modbus/RTU protocol, optional 4-20mA output, and can seamlessly connect to PLC, DCS, SCADA or IoT platforms.

• Installation and Maintenance Optimization: Submersible installation (3/4NPT), low installation distance requirements (side wall ≥2cm, bottom ≥10cm). The measurement window is simple to clean and maintain. The design without a built-in cleaning brush reduces mechanical failure points and keeps overall maintenance costs low.

These advantages enable the NBL-CDOM-406-S to maintain data consistency under complex water quality conditions, significantly reducing on-site operation and maintenance workload, and meeting the strict requirements of engineering projects for reliability and real-time performance.

Technical Specifications

Note: The sensor connector is M16-5-core waterproof male connector. The cable is 5-core shielded wire, green wire is 485B, and yellow wire is for current output (leave floating when not in use).

NBL-CDOM-406-S Online Colored Dissolved Organic Matter Sensor Application Scenarios

1. Drinking Water Sources and Surface Water Monitoring: Continuous monitoring of CDOM concentration at lake, reservoir and river water intakes to assess organic pollution status and ensure water supply safety.

2. Industrial Wastewater Treatment: Wastewater treatment systems in chemical, pharmaceutical, printing and dyeing industries to track organic matter changes in real time, optimize treatment processes and ensure compliant discharge.

3. Municipal Wastewater Treatment Plants: CDOM monitoring at inlet and outlet to assist process adjustment and evaluate organic load and treatment efficiency.

4. Rivers, Lakes and Marine Environment Monitoring: Deployment in environmental automatic stations to monitor terrestrial organic matter input and support water bloom early warning and ecological health assessment.

5. Wetland and Landscape Water Body Management: Organic pollution control in urban water bodies to maintain ecological balance.

6. Scientific Research and Water Quality Investigation: Combined with multi-parameter sensors to provide high-resolution CDOM data, supporting organic matter source analysis and environmental model construction.

Combined with NiuBoL COD, chlorophyll, turbidity and other sensors, it can form a complete water quality organic and biological parameter monitoring platform.

Installation and Wiring

Installation Requirements

• Adopt submersible installation, keep a distance of more than 2cm from the side wall and more than 10cm from the bottom to avoid interference from wall reflection or attachments.

• It is recommended to install in flowing or mixed areas to ensure the measurement window fully contacts the water to be measured.

Electrical Wiring (5-core shielded wire)

• Red wire: Power positive (12～24VDC)

• Black wire: Ground (GND)

• Blue wire: RS-485 A

• Green wire: RS-485 B

• Yellow wire: Current output (4-20mA, leave floating when not in use)

After wiring, please carefully check the sequence to avoid losses caused by incorrect connections. When the cable is immersed in water (including seawater) for a long time or exposed to air, all wiring points must be waterproofed, and cables with certain corrosion resistance should be selected. Confirm the wiring is correct before powering on.

NBL-CDOM-406-S Online Colored Dissolved Organic Matter Sensor Maintenance Guide

The cleanliness of the measurement window is critical to accurate readings. The sensor outer surface can be rinsed with tap water. Residual dirt can be wiped with a soft cloth dipped in mild household detergent. Avoid tightening the cable during normal operation to prevent internal wire breakage. The sensor interior consists of precision optical and electronic components with no user-maintainable parts. Please avoid severe mechanical impact.

Calibration Method:

• Zero point calibration: Place the sensor vertically in distilled water, with the front end at least 10cm from the bottom of the bucket, stabilize for 3～5 minutes and then perform zero point calibration.

• Slope calibration: Place in standard solution, with the front end at least 10cm from the bottom, stabilize and then perform slope calibration.

Please refer to the operation manual attached randomly for specific operation instructions. Calibration frequency should be determined according to the requirements of the competent authority or actual usage conditions.

FAQ

Q1: What is the measurement principle of the NBL-CDOM-406-S?

A: It adopts the fluorescence method, utilizing the absorption and emission peak characteristics of colored dissolved organic matter (CDOM) to achieve detection through the relationship between fluorescence intensity and concentration.

Q2: What are the advantages of the UV LED light source?

A: The UV LED light source has high stability, long service life and small drift. Combined with AC drive, it effectively filters natural light interference and improves measurement reliability in outdoor environments.

Q3: Is it suitable for seawater environments?

A: Yes. The 316L stainless steel housing is corrosion-resistant, and IP68 protection supports long-term immersion in seawater. However, it is recommended to regularly check the cleanliness of the measurement window in high salinity environments.

Q4: How to integrate with PLC or SCADA systems?

A: The sensor supports RS-485 Modbus/RTU protocol (optional 4-20mA) and can be directly connected to industrial controllers. NiuBoL provides protocol documents and technical support for quick integration.

Q5: What to do when the measured value fluctuates?

A: First clean the surface of the measurement window and check for any foreign matter attachment; confirm that the cable connection is reliable and the power supply voltage is stable. If the problem persists, please contact technical support.

Q6: Does the cable length support customization?

A: Yes, the standard length is 5 meters and can be customized according to project requirements. Please specify the length requirement when ordering and pay attention to waterproof and corrosion-resistant specifications.

Q7: Is the low power consumption design suitable for remote monitoring?

A: Yes. The 0.2W@12V low power consumption feature is very suitable for deployment in solar-powered or unattended water quality monitoring stations.

Q8: What is the sensor calibration frequency?

A: Perform two-point calibration according to the requirements of the competent authority or actual drift conditions. The sensor has high stability and low daily maintenance requirements.

Summary and Cooperation Invitation

The NiuBoL NBL-CDOM-406-S online colored dissolved organic matter sensor takes high-precision fluorescence detection, UV LED anti-interference design, automatic temperature compensation and excellent integration as its core, providing a stable and reliable online solution for water quality organic pollution monitoring. It helps system integrators and engineering contractors achieve real-time data collection, pollution tracing and water quality management, effectively improving the technical level and operational efficiency of monitoring systems.

If your project involves drinking water source protection, industrial wastewater treatment, river and lake marine environment monitoring or water quality scientific research platform construction, please feel free to contact the NiuBoL professional team. We can provide selection suggestions, integration solution support and on-site debugging assistance according to specific working conditions. Scan the contact information on the page or visit the NiuBoL official website to obtain the complete product manual, typical cases and the latest technical materials, and jointly build an efficient and intelligent industrial IoT water quality monitoring system.