Water Turbidity Sensor: Working Principle, Core Role & NiuBoL Technical Analysis

I. Core Concept and Important Role of Water Turbidity Sensors

With global environmental issues becoming increasingly prominent, efficient and accurate real-time monitoring of water resources has become a core task in environmental protection and water management. As an important device in water quality monitoring, the water turbidity sensor plays an irreplaceable role.

1. Definition & Meaning of Turbidity

A water turbidity sensor is an instrument used to measure the concentration of suspended particles and the transparency of water bodies.

Turbidity: Reflects the degree to which suspended substances (such as sediment, clay, organic matter, microorganisms, etc.) in water scatter or absorb light. Higher turbidity values indicate cloudier water. Internationally, NTU (Nephelometric Turbidity Unit) is commonly used as the unit of turbidity.

2. Key Roles & Application Scenarios

The water turbidity sensor serves as the “eyes” of water quality management, providing critical suspended solids data in the following fields:

II. Detailed Working Principle: Light Scattering

1. Basic Principle: Light Scattering

When a beam of light enters the water, suspended particles cause scattering and partial absorption. The more particles, the stronger the scattered light intensity. The sensor calculates turbidity by capturing and measuring this scattered light.

2. Core Technology: 90° Scattering Method

NiuBoL sensors (e.g., NBL-ZS-206) adopt the internationally standard 90° scattering method, complying with EN27027 and ISO7027 standards.

• Light Source: 860 nm infrared LED — eliminates interference from water color

• Measurement: Detects scattered light intensity at 90° to the incident beam — excellent linear relationship with particle concentration

• Signal Conversion: Photodiode receives 90° scattered light → converts to electrical signal → amplification, processing, and linearization → outputs NTU value

3. NBL-ZS-206 Features

• Built-in temperature compensation (Pt1000) eliminates temperature effects

• Stable infrared LED light source with long lifespan

• Fiber optic structure strongly suppresses stray light interference

III. NBL-ZS-206 Technical Specifications & Installation

1. Core Technical Parameters

2. Maintenance & Calibration

• Cleaning: Rinse with tap water; use soft cloth + neutral detergent for stubborn dirt

• Zero Calibration: Immerse in zero-turbidity water (ultra-pure) for 3–5 min → calibrate

• Span Calibration: Immerse in known standard solution → adjust to match standard value

FAQ

1. Why use infrared light?
A: ISO7027 specifies 860 nm infrared to eliminate interference from water color.

2. What does NTU mean?
A: Nephelometric Turbidity Unit — measures 90° scattered light intensity.

3. Can it identify particle types?
A: No — only total concentration. Additional instruments needed for particle analysis.

4. What does IP68 mean?
A: Fully dustproof and submersible (tested to 20 m depth).

5. Why temperature compensation?
A: Temperature affects light refraction and particle behavior — compensation ensures accuracy.

6. Advantages of RS-485 & Modbus/RTU?
A: Long-distance, multi-device networking, easy integration with PLCs and loggers.

7. When to clean/calibrate?
A: Clean when biofilm/dirt visible; calibrate when readings drift from lab standards.

8. Accuracy at 20 m depth?
A: Pressure within design limits does not affect optical measurement.

9. Zero vs. span calibration?
A: Zero sets baseline in pure water; span ensures linearity across full range.

10. Custom cable length?
A: Yes — NiuBoL offers customization (standard 5 m).

11. What certifications does NiuBoL have?
A: CE, ISO9001, RoHS, and nationally recognized meteorological calibration certificates.

Summary

The water turbidity sensor is the cornerstone of modern environmental monitoring and water treatment. Represented by the NiuBoL NBL-ZS-206, with its ISO7027-compliant 90° scattering method, infrared light source, and IP68 protection, it delivers high reliability, stability, easy integration, and low power consumption.

As requirements for water quality safety and environmental regulation continue to rise, turbidity sensors are evolving toward greater intelligence and maintenance-free operation — serving not only as tools for monitoring water health but also as critical technical support for ensuring drinking water safety and ecological stability.

Are you currently looking for a solution for a specific water quality monitoring project? I can provide detailed product selection and quotation based on your range and application environment.

NBL-ZS-206 Online Turbidity Water Quality Sensor Data Sheet

NBL-ZS-206 Online Turbidity Water Quality Sensor.pdf