High Accuracy Digital Total Chlorine Sensor RS485 4-20mA Output

Total Chlorine Digital Sensor RS485 4-20mA output

>>Overview

Total chlorine refers to chlorine present in the form of free chlorine or combined chlorine (referring to chlorine existing as chloramine and organic chloramine forms) or a combination of both, i.e., the sum of combined chlorine and free chlorine, also known as total residual chlorine. When chlorine is added to water, it undergoes a series of chemical reactions that vary depending on water quality characteristics. When ammonia nitrogen exists in water, HOCl reacts with ammonia to form compounds called amines (commonly known as chloramines). Residual chlorine electrodes primarily measure HOCl. In regions with high ammonia nitrogen content in water, where disinfection mainly relies on chloramines, total residual chlorine testing is typically required.

This sensor employs a three-electrode system with a specialized membrane structure that enhances mechanical stress resistance and chemical tolerance while remaining unaffected by pH levels. It is suitable for various water treatment applications, including seawater, brine (15% NaCl), and water environments containing surfactants. The electrode outputs 4-20mA/RS485/0~±2V standard signals that can directly connect to secondary instruments, PLCs, RTUs, and other intelligent terminal devices.

>>Feature

▪ Utilizes a membrane method to accelerate response time and ensure stable signals.
▪ The electrode casing is constructed with POM and 316 stainless steel, capable of withstanding temperatures ranging from 0 to 45°C.
▪ The leads are made of pure copper, enabling direct remote transmission. Compared to copper-zinc alloy leads, they deliver more accurate and stable signal performance.

>>Technical Parameter

Measurement Variable‌: Total Chlorine

Calibration Method‌: Zero-point drift-free; Single-point slope calibration based on chemical method

pH Range‌: 4.0–12.0

Operating Temperature‌: 0–45°C

Maximum Pressure‌: 2.0 bar

Flow Rate‌: 15–30 L/h (in flow cell)

Response Time‌: Initial polarization time: ~2 hours; T90 response time: 2 minutes

Drift‌: ≤ -1% per month in drinking water at 25°C, pH 7.2

Supply Voltage‌: 9–36 VDC 

Output Signal‌: Two-wire 4-20mA; RS485; 0~±2V; Built-in temperature compensation

Maintenance Cycle‌: Membrane cap lifespan: 1 year; Electrolyte replacement interval: 1 year