Nios Ii Sopc Based Plc System

PLC (Programmable Logic Controller) is a general-purpose computer technology as the core of industrial control devices. It will relay the traditional and computer control technology and communication technology into one, with a powerful, environmental adaptability, simple and easy to use programming features, in the industrial automation field widely. Currently, the domestic market by foreign products PLC high degree of monopoly. Research on the PLC system will help improve the level of China's equipment manufacturing industry, breaking the monopoly of foreign products.Based on the FPGA platform is designed and implemented to NIOS II core SOPC (System on Programmable Chip) system, with a variety of peripheral interface circuit, formed part of the PLC hardware.In this paper, Mitsubishi FX1's basic instruction set as the goal, it first instruction level LALR (1) grammar, by the design and implementation of this article law lexical analyzer and parser, which can NIOS II software system Mitsubishi FX1 PLC interpreted the basic instruction set.Experiments show that the implementation of the system can correctly interpret the basic instructions FX1 to achieve the basic functions of PLC. Constructed by the SOPC Technology PLC system that can effectively use the programmable FPGA hardware logic resources, user-customizable dedicated PLC system, but also has high performance and economy.