Chemical Oxygen Demand Sensor (COD Sensor) | Online COD Digital Probe

This industrial online Chemical Oxygen Demand (COD) sensor adopts advanced UV absorption spectroscopy (UV254) measurement principle, with integrated digital signal processing, built-in temperature compensation and IP68 waterproof structure. It provides standard RS485 (Modbus-RTU) digital output, featuring fast response, reagent-free operation, low maintenance and high stability. It is widely used in surface water, municipal wastewater, industrial effluent, aquaculture and process water monitoring, and can be seamlessly connected with PLC, DCS and MTW series controllers.

This online COD sensor is an intelligent monitoring probe designed for real-time measurement of organic pollution in water. It uses the UV absorption spectroscopy principle (254nm), which correlates the UV absorbance of water with the Chemical Oxygen Demand (COD), Total Organic Carbon (TOC) and other organic parameters. This optical method requires no chemical reagents, no digestion process, and achieves real-time online monitoring with a response time of seconds, greatly reducing operating costs and environmental pollution.

The optical window is made of high-strength sapphire with anti-fouling coating, effectively reducing contamination and ensuring stable measurement in various water environments. Built-in temperature sensor realizes automatic temperature compensation, correcting measurement drift caused by temperature changes. The whole machine adopts digital signal conditioning and electrical isolation design, with strong anti-electromagnetic interference ability, supporting stable long-distance data transmission via RS485 Modbus-RTU.

The probe housing is made of corrosion-resistant PPS/PEEK engineering plastic and 316L stainless steel, suitable for long-term submerged installation in industrial and environmental water systems. It supports standard solution calibration (phthalic acid potassium hydrogen standard solution), with calibration data power-off storage and fault self-diagnosis functions. It is an ideal tool for organic pollution monitoring, effluent compliance control and process optimization.

Technical Parameters

Specification Item	Parameter Description
Temperature range	0–80°c
Pressure	0–3 bar
Sensor material	stainless steel, carbon steel, or copper(customizable)
Resolution	0.000001mm\a
Measurement range	0 - 5mm\a
Accuracy	≤±3.0%
Compensation mode	manual\automatic
Output signal	4-20ma,rs485(modbus-rtu)
Line length	5 meters (customizable)
Current accuracy	1%fs
Housing material	pc,pbt corrosion-resistant
Output load	＜750Ω
Connecting thread	m39*1.5,npt3/4
Calibration method	laboratory comparative method
Protection level	ip68

Application Fields

Municipal Wastewater Treatment: Real-time COD monitoring in influent, aeration tanks, secondary sedimentation tanks and effluent to ensure discharge compliance.
Industrial Wastewater: COD control in chemical, petrochemical, textile printing & dyeing, papermaking, food & beverage and pharmaceutical wastewater.
Surface Water & Environmental Monitoring: Organic pollution detection in rivers, lakes, reservoirs and coastal waters for ecological evaluation.
Aquaculture: COD monitoring in ponds and recirculating aquaculture systems (RAS) to assess water quality and organic load.
Process Water: Organic pollution control in cooling water, boiler water and industrial process water systems.
Drinking Water Treatment: Organic matter monitoring in raw water and finished water to ensure drinking water safety.
Laboratory & Portable Testing: Suitable for field rapid detection and laboratory analysis of organic pollution.