This paper mainly exponuds the design of the automatic control of the ball size sorting system,which is a design applies the high performance and low cost micro-programmable conroller FX series PLC of Mitsubishi company。The design of the system take full advantage of a study on the various aspects of the PLC design knowledge and methods,coupled wonderfully with the use of stepping motor make the manipulator finish a series of progress such as ascending , overhanging ,judge, declined,crawl,swing,decling, release ahd restoration。The realization and application of this system fully embodies the application of PLCin industrial spots。This system can be applied to a wider range ,if we change data according to design and demand。As the limitation of designer`s knowledge and lack of experience of design ,there must be seamless。Hope teachers give criticisms,correct and understanding。
Key words:Programmable Logic Controller,manipulator,automatic control system of the ball size sorting,and stepper motor。