Yexsensor YEX-CL-406-S Online Residual Chlorine Sensor

Yexsensor YEX-CL-406-S online residual chlorine sensor is a dedicated online monitoring device developed for system integrators, IoT solution providers and water treatment engineering companies. The sensor is based on the constant voltage method and can achieve continuous and accurate measurement of free residual chlorine (mainly in the form of HClO) in water, meeting the needs of drinking water disinfection process control, pipe network end monitoring and industrial circulating water sterilization management.

In the fields of drinking water safety and industrial water treatment, residual chlorine concentration is a key indicator to ensure disinfection effect and prevent excessive dosing. Traditional DPD colorimetric method relies on manual sampling or reagent consumption, while YEX-CL-406-S provides a reagent-free, real-time online measurement method, providing stable data support for PLC, DCS or SCADA systems, helping to optimize disinfection process, compliance management and improve operation and maintenance efficiency.

YEX-CL-406-S Online Residual Chlorine Sensor Working Principle

YEX-CL-406-S adopts constant voltage method (constant potential amperometric method). The sensor contains working electrode, reference electrode and counter electrode. A constant voltage is applied between the working electrode and the reference electrode to maintain a stable potential at the working electrode. Free residual chlorine (hypochlorous acid HClO and hypochlorite OCl⁻) in water undergoes electrocatalytic reduction reaction on the electrode surface, and the generated current signal is proportional to the residual chlorine concentration.

The built-in Pt1000 temperature sensor realizes automatic temperature compensation, reducing the influence of temperature changes on measurement results. This method has rapid response and good applicability to water samples with pH in the range of 4~9, suitable for continuous monitoring of drinking water and circulating water systems.

YEX-CL-406-S Online Residual Chlorine Sensor Product Features

YEX-CL-406-S has multiple practical advantages in engineering applications:

• Constant voltage method measurement, no need to add chemical reagents, avoiding secondary pollution

• Dual range design, meeting the needs of low concentration drinking water and higher concentration industrial water treatment

• Automatic temperature compensation (Pt1000), improving measurement stability under different working conditions

• Supports RS-485 Modbus/RTU protocol and optional 4-20 mA current output, convenient for system integration

• Equipped with flow cell installation, ensuring stable flow rate and high measurement repeatability

• POM and 316L stainless steel shell combination, IP68 protection rating, strong corrosion resistance

• Low power consumption design (0.2 W @ 12 V), adapting to on-site power supply conditions

• Fast response time (T90 < 90 s), minimum detection limit 0.05 mg/L

These features make YEX-CL-406-S a highly reliable and easy-to-maintain preferred device in drinking water and circulating water residual chlorine monitoring projects.

YEX-CL-406-S Online Residual Chlorine Sensor Technical Parameters

Technical Specifications Table

Installation and Electrical Connection

Installation Guide

YEX-CL-406-S adopts flow cell installation method. During installation, the sensor should be tightly connected with the supporting flow cell to ensure that the measurement part is located near the water inlet of the flow cell and avoid facing the water outlet directly. It is recommended to control the flow rate of the flow cell within 30-60 L/h to ensure sufficient water sample renewal and measurement accuracy. Stable flow rate helps reduce bubble interference and improve data stability.

Electrical Connection

The sensor adopts 5-core twisted shielded cable, and the wire sequence is defined as follows:

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

• Black wire: Ground (GND)

• Blue wire: RS-485 A

• Green wire: RS-485 B

• Yellow wire: Current output (optional; if not used, it can be left floating)

Before wiring, be sure to carefully check the sequence to prevent wiring errors. All wiring terminals need waterproof treatment, and the cable should have corrosion resistance to adapt to long-term immersion or humid industrial environments.

YEX-CL-406-S Online Residual Chlorine Sensor Maintenance and Care

The maintenance focus of YEX-CL-406-S is electrode activation and regular calibration, with low overall maintenance requirements.

Maintenance Methods

• New electrode or long-idle electrode: Soak and activate in tap water for 24 hours before use. If the reading deviation is large, it is recommended to perform zero point and slope calibration or return to factory for inspection.

• Zero point calibration: Place the sensor in chlorine-free water, and execute the zero point calibration command after the value stabilizes.

• Slope calibration: Install the sensor in the flow cell, pass flowing residual chlorine standard solution, and execute the slope calibration command after the value stabilizes. For low range, 1～2 mg/L HClO standard solution is recommended; for high range, 10～20 mg/L standard solution is recommended. Standard solution preparation can refer to national standard residual chlorine determination methods.

The sensor has been calibrated before leaving the factory. It is not recommended to perform frequent self-calibration unless necessary to avoid the influence of standard solution preparation errors on accuracy.

Precautions

• Working pH range is 4～9; exceeding the range may affect measurement accuracy

• Regularly check whether the flow rate of the flow cell is stable

• Avoid the sensor from being subjected to severe impact and protect the sensitive parts of the electrode

YEX-CL-406-S Online Residual Chlorine Sensor Application Scenarios

Yexsensor YEX-CL-406-S is widely applicable to water treatment engineering projects that require continuous residual chlorine monitoring.

1. Drinking Water Treatment Plants
   Deployed in post-filter water, clean water tanks and factory outlet pipelines to monitor residual chlorine residue after disinfection in real time, ensure that factory water meets hygiene standards, optimize chlorine dosing, and reduce the generation of disinfection by-products.

2. Drinking Water Distribution Network
   Installed at the end of the pipe network or monitoring nodes to prevent secondary pollution from causing residual chlorine decay, ensure water quality safety at the user end, and support smart water remote monitoring.

3. Swimming Pools and Water Parks
   Continuously monitor residual chlorine concentration in circulating water to maintain effective sterilization levels and avoid excessive chlorine irritating the human body or corroding equipment.

4. Industrial Cooling Circulating Water Systems
   Monitor residual chlorine in cooling towers and heat exchanger circulating loops to control biological scale growth, extend equipment service life and reduce chemical consumption.

5. Bottling Plants and Food & Beverage Processing
   Ensure that production water residual chlorine meets process requirements, prevent microbial contamination, and ensure product safety and quality stability.

6. Other Water Quality Treatment Projects
   Suitable for various occasions requiring precise disinfection control, such as hospital water, electronic industry pure water pretreatment, etc.

In the above scenarios, YEX-CL-406-S effectively simplifies system integration and reduces long-term operating costs with its reagent-free design, standard communication protocol and supporting flow cell installation.

Frequently Asked Questions (FAQ)

Q1: What measurement principle does YEX-CL-406-S adopt?

A1: The sensor is based on the constant voltage method and realizes quantitative detection by measuring the current signal generated by residual chlorine reduction on the electrode surface.

Q2: What range options does the sensor provide?

A2: Low range 0~2.000 mg/L (resolution 0.001 mg/L) and high range 0~20.00 mg/L (resolution 0.01 mg/L), meeting different application requirements.

Q3: What output methods are supported?

A3: Standard RS-485 Modbus/RTU protocol, optional 4-20 mA current output, convenient for access to various control systems.

Q4: What are the requirements for flow rate during installation?

A4: It is recommended to use the supporting flow cell, and control the flow rate at 30-60 L/h to ensure smooth water sample renewal and improve measurement accuracy.

Q5: How to calibrate the sensor?

A5: Two-point calibration is adopted: zero point uses chlorine-free water, and slope uses flowing residual chlorine standard solution. It has been calibrated before leaving the factory, and self-operation is not recommended unless necessary.

Q6: What needs to be done for new electrodes or after long-term storage?

A6: Soak and activate in tap water for 24 hours before use. If the reading deviation is large, perform calibration or return to factory for inspection.

Q7: What is the working pH and temperature range?

A7: Working temperature 5～50℃, pH range 4～9, with built-in automatic temperature compensation function.

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

A8: It has undergone 72-hour aging and stability testing before leaving the factory. Batches with a defect rate of 2% can be returned directly. The manufacturer provides one-year warranty and technical support services for system integrators.

Summary

Yexsensor YEX-CL-406-S online residual chlorine sensor takes the constant voltage method as the core technology, combined with dual range design, automatic temperature compensation and standard communication interface, providing accurate and stable solutions for online residual chlorine monitoring in drinking water and industrial circulating water. Its flow cell installation method and low maintenance characteristics fully meet the actual needs of water treatment projects.

Through real-time and reliable residual chlorine data, the sensor helps users optimize disinfection processes, ensure water quality safety, and effectively control chemical agent usage costs. It has become an important choice for many engineering companies in the disinfection monitoring link.

If you need detailed product quotation, technical specification sheet, selection guidance, flow cell configuration or project application cases, please contact the Yexsensor professional team. We will provide targeted technical support and complete solutions according to your specific working conditions and control system requirements, helping projects to be implemented efficiently and operate stably for a long time.