Distributed Numerical Control System Communications Technology Research And Development

DNC technology is one of the automatic manufacturing technology which is performed by one computer linked by some NC equipments. And it is the important important bottom technology in realizing FMS and CIMS. DNC system also can be applied independently as a layer of factory automation system. As compared with FMS, DNC has the merit of lower investment, quick effection and good flexity. It is a integrated control system of some NC equipments, which can have a great deal of human-computer interaction.At first, the concept and the development of DNC are introduced in this paper, and the three main DNC communication techniques are analyed. Then give the First Machine Tool Factory of QingHai a whole design of DNC system structure.According to the manufacture facts, presents the integration methods of typical NC equipments in synthesis.In this essay, we mainly study the asynchronous serial communication software of the DNC host computer. The protocol of physical layer, data link layer, application layer that corresponded to serial communication is analyzed in detail. The software enables the DNC system have the ability to transmit NC program, receive NC program, and to query the status of NC equipment. By use of multi_thread technique, the software resolve the problem of communication with multi_port simultaneously. DLL technique is also adopted to resolve the integration problem in DNC system which have different DNC protocols easily, and make the DNC system have good performance of expansion.In the end, the structure and communication realization of one kind of promising DNC system based on CANBus is discussed.