Cod monitor,also known as cod measuring instrument, cod water quality online automatic monitor, cod monitor uses advanced water quality sensors and technology to accurately measure various indicators, playing an important role in water resources protection and management.

Principle:
 A mixture of water sample, potassium dichromate digestion solution, silver sulfate solution (silver sulfate is added as a catalyst to more effectively oxidize linear fatty compounds), and mercury sulfate solution is heated to 165°C, and the dichromate ion oxidation solution The color will change after the organic matter in the analyzer detects this color change, and converts this change into a COD value and outputs it.The amount of dichromate ions consumed is equivalent to the amount of oxidizable organic matter.
 Biting inorganic substances in water samples, such as nitrite, sulfide and ferrous ions, will react with potassium dichromate and affect the measurement results. The potassium dichromate they consume will be recorded in the measurement results. The test results were on the high side.
 The interference of chloride ions in water samples can be eliminated by adding mercury sulfate, because chloride ions can form very stable mercury chloride with mercury polymers.
 Technical parameter
 method based on: dichromate spectrophotometry.
 Implementation standard: HJ377-2019
 Star measurement range: (0-5000) mg/L
 Lower limit of fixed halo: 15 mg/L (indication error ±30%) Repeatability: ±5%
 Low concentration drift: ±5 mg/L
 High concentration Drift: ±5%
 

　　Extended range: Indication error: ±3%, Gravity: ±5%, High concentration drift: ±3%, Gas ion influence test: ±10% Measurement cycle: The minimum measurement cycle is 20 minutes, according to the actual water sample
 , The digestion time can be modified arbitrarily from 5 to 120 minutes.
 Sampling period: time interval (arbitrarily adjustable from 10 to 9999min) and hourly measurement mode.
 Calibration period:]~99 days, adjustable at any time and at any interval.
 Maintenance cycle: generally once a month, about 60 minutes each time.
 Output: RS-232, RS-485, 4-20mA (optional)
 Environmental requirements: Indoors with adjustable temperature, recommended temperature +5~28°C; humidity ±90% (no condensation).
 Power supply: 220V
 instrument features
 automatic standard sample verification function.
 No data will be lost in case of abnormal alarm and power outage.
 It has the function of adding identification to different test data.
 It can realize serial port output and network port output of monitoring data.
 It has the function of collecting and storing analysis waste liquid and cleaning waste water separately.
 It has multiple ranges and can automatically switch ranges. The instrument displays the final test results.
 It has large-capacity storage, with no less than 5 years of historical data storage (measurement cycle lh/time).
 After abnormal reset and power outage, the instrument automatically discharges the remaining reactants in the instrument and automatically returns to working status.
 It has the functions of automatic collection, storage, interrogation, display and output of all data and instrument parameter operation logs.
 Select the valve components, select the reagent sampling timing, the channels are flexible and diverse, and have the advantages of minimum volume, easy maintenance and long life.
 It has a digital communication interface, which outputs instructions, relevant data and operation logs through the digital communication interface, and can receive remote control instructions from the management platform, including remote start and remote time synchronization functions.