Research On The Technology Of Soft Control Cards Based On The Industrial Ethernet

At present, the development of industry depends on numerical control technology and field-bus technology. In the open NC system, the flexibility and variability of the software module and hardware platform makes the CNC technology have a great progress. Real-time Ethernet overcomes the disadvantages of industrial Ethernet real-time problem in order to ensure the accuracy of processing requirements. This paper presents a design scheme of software control part of open CNC system based on the real-time Ethernet, and presents the application examples of the development.The paper begins with a review of the development process of numerical control system and industrial Ethernet, the development of open CNC system are also introduced in this paper. Then it introduces the generation of industrial Ethernet and illustrates the real-time problem. And second, the technology characteristics of the EtherMAC real-time Ethernet bus are described, and analyzed functions of slave station interface cards based on this Ethernet protocol. Then, this paper focuses on the research about the driver software of slave station interface cards; the object-oriented design method is proposed. It presents using the object-oriented design method to divide the driver software into a plurality of modules. The driver software of slave station interface cards is divided into several different functional classes; these classes are mainly responsible for the communication and cards’function. When users use these slave station interface cards, they can choose the corresponding software driver module according to the card. At the same time, the hardware and software architecture of open CNC based on EtherMAC are introduced, the paper elaborates the division and function of the soft control card, it also introduces the modules and the internal data flow.Finally, using the above mentioned soft card to develop a four axis milling machine system, we determine the plan of the hardware of the system through the analysis of the user’s processing requirements, such as the choice of slave station interface cards, keyboard operation panel and the choice of industrial PC. According to the requirements of the software functions, the system task is divided into real-time tasks and non-real-time tasks; we use two different programming languages to develop these two tasks. Then, the user’s interface of system, interfaces of control modules and the communication between modules are mentioned.