The Development And Construction Of A Pneumatic Controlled Electronic Organ Performing System Based On PLC

With the development of control theory and microelectronic technology, there have been great changes in the control methods of pneumatic equipment. The combination of pneumatics, electronic technology and computer technology drives pneumatic components to advance toward miniaturization, intelligent and integration, and which further promote the application of pneumatic technology in manufacturing and automaton industry. As a new kind of industrial controller, PLC has been widely used in pneumatic equipment due to its good reliability and technical advancement, and it is one of the key directions for the development of the pneumatic equipment from the traditional relayed control into PLC control.In this paper, the characteristics of pneumatic control technology and its development are analyzed first, followed by detailed discussion of the widely used sequential control technology, including the basic principles and its application in industry. Based on the basic function and requirement and the way of design of the pneumatic controlled performing system, as well as the comparison between relayed controller, sequential controller and PLC, PLC is selected as the key controller of the system, mainly responsible for the control of electromagnetic valves.A conventional pneumatic system usually has low reliability for it is consisted of many single functional components which are arranged separately. Besides, it brings much inconvenience for system fabrication, measurement, monitoring and maintenance. So in this equipment, after detailed study and comparison of the characteristics of several kinds of valve terminals, and take the practical requirement of the performing system into consideration, the manifold valve with multiple terminals is selected. The valve terminal aims to reduce the time limit and helps to acquire high reliability.To software design, this paper describes the difference between the traditional programming method using ladder logic and the programming methods for sequential control based on sequential function charts. Then the controlling program is carried out by using STL of Mitsubishi, which strongly matches the demands of multiple steps and rapid response ability of the system. Besides, this programming method is much easier than other methods and helps to reduce the scanning time a lot. A real time monitoring system is produced by use of Mitsubishi human machine interface GOT.The practical operation proves that this pneumatic controlled performing system has strong stability, and presents well the advantages of pneumatic technology such as good reliability and high flexibility, which also acts as the base for further design and application of similar systems.