Accurate and intelligent carbon source adding control system and method

The invention discloses a carbon source accurate intelligent feeding control system and method, the system comprises an online monitoring system, a carbon source feeding system, a first PLC controller, a second PLC controller and a third PLC controller, the carbon source feeding system is electrically connected with the first PLC controller to control the feeding of a carbon source; the online monitoring system collects inlet and outlet water TN, inlet water instantaneous flow, ammonia nitrogen and COD data and anoxic zone DO, pH values and ORP values through instruments, the instruments of the online monitoring system are all electrically connected with the second PLC, the third PLC serves as a sampling and sample measuring master control PLC and receives a sample measuring command of the second PLC, and the third PLC is electrically connected with the second PLC. A command is sent to an instrument for sampling, sample reserving and detection, a sample detection result is fed back to the second PLC, and a wa