Application Of USB Communication In The Relay Protection Test System

Celerity, nicety and counteracting disturbance are the important problems in industrydesign. Generally in industry project communication is the bottleneck of the system. If theproblem is resolved commendably, the system performance will be improved greatly. Inthe traditional industry communication, the transmitting interface is RS-232C. While theRS-232C has the disadvantage of slow speed, easily disturbed and inconvenient to link.Therefore the improvement for the communication mode is an imperative problem. USB communication Version 1.1 is the general protocol for the connection betweencomputers and their peripheries. Compared with the other communication interfaces, USBhas the most virtue of easy to use, plugging and playing and high-speed transmitting. Andthe entire configuration is finished automatically by the computer system instead of theintervening of users. So the USB has great conveniences for the user, which is the mainpredominance. With the promotion of the USB 2.0 protocol, and the raising oftransmitting speed, USB communication will be widely used in the industry applications. In this paper, for the problem of communication speed and counteracting disturbancein the Relay Protection Test System, the scheme of USB communication is promoted.These are introduced in the paper including background of the USB's promotion, itshistory and the virtue and shortcoming, USB topology and some important conceptions.And the USB communication principle is simply introduced. It is emphasized that in theRelay Protection Test System, USB communication is an ideal scheme. Because of theresource finity of the CPU (80C320), the USB interrupt transfer is the most suitable forthe system according to the analyse for the CPU. And this is verified by the theory andpractice. The D12 is a cost and feature optimized USB device. It is normally used in microcontroller based systems and communicates with the system micro controller over thehigh-speed general-purpose parallel interface. It also supports local DMA transfer. Thetransfer speed is up to 2MB/s. This modular approach to implementing USB interface 2allows the designer to choose the optimum system micro controller from the availablewide variety. This flexibility cuts down the development time, risks and costs by allowingthe use of the existing architecture and minimizes firmware investments. This results inthe fastest way to develop the most cost effective USB peripheral solution. Now there aremany applications about USB, which is helpful for developing the new Relay ProtectionTest System. In this paper, the software and hardware for the new Relay Protection TestSystem designed with this chip are specified and some relative technologies are analyzed.