Design And Implementation Of Soft PLC For Open CNC

Open CNC is a key development of CNC technology. As an important component of CNC, traditional structure of PLC system is sealed, and unable to meet the demand for the openness. With the development of computer technology, soft PLC technology has become a trend in open CNC system, which is based on the PC hardware platform and realized with software. The main study of the thesis is to design and implement soft PLC which is based on the Lantian open CNC.In the process of design and implementation, this thesis focuses on the following two aspects:Design and implementation of the developing system. The developing system provides a logic program development environment. It also can compile a logic program into an object code and download the object code to the runtime system. In the developing system, the compiler is an important part. This thesis researches the modules of the compiler and solves the problems encountered during the compiler design.Design and implementation of the runtime system. The runtime system executes the object code which is downloaded from the developing system and controls the related devices. To meet the requirements for the open CNC and solve the limitations of RTLinux, the runtime system is composed of virtual machine, soft PLC manager, hardware abstract layer and memory manger.After the test and practical application, it is showed that the soft PLC can correctly execute logic programs and control the devices. And it can suitable for the open NC.