The Research And Design Of Compiled PLC Based On RISC

PLC is a high-reliability, flexibility, feature-rich industrial automation and control devices, which has a broad application and development prospects in industry. In recent years, with the prices of PLC continue to lower, and the rapid development of China's economy and the basis for the continuous improvement of the level of automation, more and more small and medium-sized equipment began to use PLC to control, and PLC will maintain its high growth momentum in a period of time in China. Therefore, the design of PLC became a significant issue. In this paper, discuss the research and design of compiled PLC based on the AVR microcontroller, and explore the expansion of the number of ports of PLC which was used of CAN bus to realize, the mainly work to complete of the following:(1) Firstly, the article described the produce and development of programmable logic controller and analyzed the programmable logic controller on the domestic and international situation and development trend, and briefly introduce AVR microcontroller technology and the CAN bus.(2)Analyzed the working principle and process of the explained PLC with examples, given the general system of the PLC hardware and software model, and given the compiled PLC systems model, designed PLC hardware framework which was used Reduced Instruction Set CPU of the ATmega128 AVR microcontroller series as control core.(3)Developed the PLC ladder edit environment with the compiled system, described in detail editing interface and compiler of the PLC instruction set design, integration the instructions to edit environmental directives into the menu bar and trapezoidal Map data storage and computing made a detailed description of relations.(4)Analyzed the design principles and processes of the compiler, and analyzed the process from the ladder program compiled into executable code. Focus of a ladder from the middle of the process and the use of code AVR microcontroller command system to achieve the intermediate code. (5) In the back section of the article, given the specific PLC system hardware design, including the AVR microcontroller external circuit, I/O port design, serial circuits and CAN bus interface circuit, and developed simple agreement expand the port of the PLC used CAN bus. Finally, summarized the whole text and made the subject of the research findings for further study and improve hope.