| Oxygen is highly important in metallurgical industry. In order to increase the yield of Oxygen and improve its quality, it is necessary to improve the control of the Air Separation Device.Laiwu steel Group' Ltd. has an Oxygen workshop which yield of oxygen is 12000m~3/h. Intelligent instruments and single loop adjusters were used to display and control parameters, but this system hasn' t meet the requirement of actual production. To resolve the problems, such as, the function was out-of-date, the lifespan was reaching and there was no spare part, we innovated the automatic control system of the Air Separation Device with the compact distributed control system Freelance 2000.The control scheme is proposed to the technical innovation for the Air Separation Device. The system composition, the hardware design, the software design, the system commission are discussed in detail in this thesis.The system hardware is designed according to the technological requirements, the upper computers include an engineer workstation and an operator station and the process station include two controllers that are redundant for each other. The upper computers and the process station are linking by Ethernet. There are redundant CPUs, power supplies, communication nets and operator stations that improve the reliability and the veracity of the control system.The operator software is programmed in SFC display of software package DigiTool and the human-machine interface is friendly. It can display dynamic, animated graphic displays performing data collection, data processing and data display. The program of controller is edited by function block and ladder logic of software package DigiTool, which realizes every control function of the Air Separation Device, such as anti-surge control for the Air compressor, Hydrogen flux control, logical control for molecule griddle and Argon drier, ect.
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