Based On Real-time Fieldbus Network Communication Applications

The development of computer communication and information technologies promotes the advancement of automation technology. Fieldbus technology is the result of that computer communication technology extends to industry automation field. It gradually converts the computer control system from Distributed Control System to distributed Fieldbus Control System. In order to reliably transmit real-time data over fieldbus, it is need to research on key technology of real-time network system based on fieldbus. Because of the virtues of it, such as whole digital communication, distributed control, open interconnectness, simpleness of design and installation,it will be applied in industry control field more widely and farther. As a type of network which is applied in industry control field, it should satisfy the demand of trasmiting network data reliably and predictability. Though fieldbus protocols already have basic architecture to transmit real-time network data, in order to entirely realize this goal, the key technologies about the real-time network system based on field bus should be researched. At the First part of this paper, some typical fieldbus protocols are introduced, and their common characters, especially in real-time communication field are discussed. After that, some typical real-time scheduling algorithms are discussed, including task scheduling algorithms which distribute the CPU computing time and network scheduling algorithms which distribute the network bandwidth resource distributing. This paper summarizes the algorithms'advantage and disadvantages after analyzing their features. MIL-STD-1553B protocol is introduced, and its features about real-time transmit transmission is analyzed. The strategies of how to choose the appropriate algorithm for real-time communication under the condition is discussed. Finally, a real-time communication network system based on MIL-STD-1553B bus is introduced. It builds a real-time communication network with the hardware platform based on MPC860 and BU61580, and software support environment based on real-time OS -CRTOS. Through deferent designs of the scheduling algorithms, it can satisfy deferent real-time communication demands under deferent network conditions which have deferent time parameters. Using this example, the application of fieldbus in the real-time communication field is discussed. As a type of real-time control network, fieldbus has outstanding real-time character. Aiming at this goal, it improves its hardware and communication protocol from traditional computer networks. Take the MIL-STD-1553B bus for example, this paper presents how to build a real-time network communication platform using fieldbus technology at theory, design and implement aspects. The system integrates...