Research Of Spot Welding Control System Based On PLC

Along with the rapid development of computer technology, the traditional industrial automation control also has a qualitative leap, from the relay control to the computer control. Programmable Logic Controller (PLC) is one kind of electronic system by using digit arithmetic operation. It is a kind of industrial computer which specially designed for complex industrial applications, it is a contemporary industrial automation pillar for its small size, high reliability, simple programming that make it be widely used.Welding process is instantaneity and there are many interference factors, In order to improve the reliability of welding joint, this paper proposed a method by combining traditional PID control and Fuzzy control together, designed a spot welding constant current Fuzzy-PID controller. In allusion to the speed of commonly used single-chip is not fast enough, Mitsubishi high-performance FX2N PLC was adopted in this paper as the control chip, meanwhile, the design work for peripheral circuit such as actuating signal circuit, sync pulse circuit and etc were finished.PLC is used as the main controller in this system, the design approach is following modular design rule and finally achieved the goal of controlling the welding machine, the system has a higher stability and more efficient. Besides, it can complete a variety of control functions, this system also can interconnect with other computers to build a communication network, it is good for integrating the production control and information management, providing a broad space for expanding the system in the future.Mitsubishi GOT1000series touch screen is used to develop human-computer interface in this paper, it can reduce the required PLC I/O numbers and make the system’s wiring simpler and standardization, meanwhile, Welding operating panel can be more nattiness, quite visually intuitive and practical. By using it, operation staff can well know the welder’s running states and error information in real time.This system achieved the expected design requirements, and it is hopeful to be used in industrial applications.