The COD online monitor utilizes potassium dichromate open reflux volumetric analysis method to oxidize the samples. Under the control of a computer, the water samples are mixed with potassium dichromate solution and concentrated sulfuric acid, with silver sulfate added as a catalyst, and the chlorine ions in the mercury sulfate complex solution are reacted. The mixture is refluxed at 165°C for a certain period of time, during which the reducing substances in the water react with the oxidizing agent. The Cr6+ in the oxidizing agent is reduced to Cr3+, causing a color change in the mixture. The increase in Cr3+ is converted to a voltage change through photometric comparison. By measuring the voltage change and using the curve to calculate, the COD value is determined.

Large Screen LCD Display: The instrument features a large screen graphic dot matrix LCD display, which not only shows the entire process flow of the analysis, but also provides a clear and direct display of measurement results, reports, and curves.

2. 4-20mA analog interface output: The 4-20mA corresponds to a linear output between zero and full scale, compatible with various standard data collectors.

3. Storage Function: The instrument is equipped with a high-capacity electronic hard drive, capable of storing ten years' worth of measurement data from the instrument's operation.

4. Range Adjustment: Select the appropriate range based on water quality to ensure measurement accuracy.

5. Heat Time Adjustment: Select heating time based on the condition of pollutants in the water to ensure complete oxidation of the contaminants.

6. Printing Function: Offers a printing output port for external printers to print documents.

7. Automated Sampling Feature: Automatically completes water sample collection.

8. Fixed-point analysis feature: Selectable analysis frequency and time (e.g., 3 times/day, 8:00, 10:00, 18:00).

9. Reagent Alert Feature: Set the remaining reagent level, and the instrument will stop operating and sound an alarm when the reagent falls below the lower limit.

10. Power Failure Protection Function: In the Main Interface and Auto-Analysis modes, if power is cut off and restored within 10 minutes without any manual operation, the instrument will automatically resume the Auto-Analysis mode; in the Manual mode, upon the same power failure, the instrument will automatically revert to the Manual mode.

Remote Control Feature: Added corresponding attachments, enabling remote monitoring of the instrument via GSM SMS.