Based On Iec61131-3 And Java Plc Simulation System Design And Implementation

With many advantages such as rich functionality, high reliability, easy to program and adapt in harsh industrial environments, PLC has an important place in the field of industrial control. As its applications in different areas and development in microprocessor technology, PLC becomes more intelligent, modular and networked. Along with the development of computer and software technology in recent decades, with computer as the hardware platform, and operating system as the software platform, it has become an important direction of the PLC research to achieve PLC functions with computing software simulation.After researches how PLC works and introduces the standards of PLC, the paper presents the detailed design ideas to achieve PLC simulation using Java language and software, and realizes the software. With PLC programming standards of IEC61131-3as a reference, the software is divided to three subsystems:Ladder Diagram drawing system, syntax checking of Ladder Diagram and Instruction list generating system, Simulation and Running system.The main task of Ladder Diagram drawing system is to draw Ladder Diagram of PLC. The system provides a set of PLC component libraries, and set a group of element cells to record the information of component draft in different cells. The edit, save and re-open of the Ladder Diagram picture are based on this construction. The system of syntax checking of Ladder Diagram will check if there is any syntax error in the Ladder Diagram. If the Ladder Diagram is compliance, it can be transformed to instruction list. There is a common method to fulfill the transform with activity on vertex map and binary tree. After introducing this method, the paper gives a method of merging series and parallel of the slip to reach the goal, and this method is proved to be proper and effective. The simulation and running system explains and executes instruction list row by row. An interface is given so the station of Ladder Diagram and status of the memory can be shown intuitively and vividly. The paper uses a PLC program of traffic light signal to verify the function of the software, and successfully achieved the control purpose.At the end of the paper, a whole of the assessment of the software is put forward; the consummate is also being brought forward.The subject is trying to use the Java language to implement the PLC simulation, and certificate the availability of Java software in the field of industrial control. Some new cogitation about soft PLC and PLC simulation are also mentioned.