PLC-based control method in diamond growth system

The invention relates to a PLC(Programmable Logic Controller)-based control method in a diamond growth system. The PLC-based control method in the diamond growth system comprises the steps that a PLCperforms an air exhaust control process on a vacuum system according to process starting signal control and feedback signals of elements in the vacuum system; the PLC performs a process control process on the vacuum system according to the feedback signals of the elements in the vacuum system so as to enter a diamond growth process; in a diamond growth process, according to a growth information formula table obtained from an upper computer, the PLC performs vacuum pressure control by utilizing the vacuum system, performs growth position control by utilizing a seeding crystal carrying disc system, performs glow control by utilizing a glow system and performs process gas control by utilizing a process gas system; and the PLC performs the air exhaust control process on the vacuum system according to process stop sign