COD-208 UV Cod Sensor

The listed COD-208 design uses a 254 nm UV channel and a reference channel for compensation. UV absorbance responds to UV-absorbing constituents; it does not directly measure oxygen consumed in a chemical digestion. A COD estimate therefore depends on the water matrix and the configured relationship to a reference COD method.

Learn how laboratory COD, UV254/SAC254 and online optical COD estimation differ. Document the selected reference method and site-validation plan before using the reported optical COD estimate for an alarm or control decision.

Calibrate for the water being monitored

• Specify the water source, expected range and reference laboratory method, including whether samples are filtered or unfiltered. Optical and laboratory results should represent the same sample fraction.
• Collect paired optical readings and laboratory COD results across the relevant process conditions. Validate the relationship on additional samples, record residual differences and reassess it when the wastewater composition changes.
• Check optical windows, bubbles, suspended particles and deposits before changing calibration. A reference-channel correction can reduce certain effects; it does not remove every interference or compensate for all changes in organic composition.

Installation and use

• Use for trend monitoring and process assessment in compatible surface-water or wastewater installations after site validation. A reading alone does not establish discharge compliance, drinking-water safety or total pollutant content.
• Keep the optical path immersed and representative of the process. Confirm mounting, flow, materials and the pressure/temperature limits of the supplied assembly.
• The listed cleaning brush assists with fouling control. Inspect and clean the windows, check brush condition and verify readings with the supplied procedure; automatic cleaning does not make the sensor maintenance-free.
• For the listed RS485 output, obtain the actual application protocol, register map, engineering units and receiving-device settings. RS485 is a digital interface, not an analog current output.