Research And Implementation On The Compiler Of The Compiled PLC

Programmable logic controller (PLC) is the critical core equipment of industrial automation, advanced manufacturing and industrial process control. With a series of advantages, such as easy to use, high reliability, strong anti-interference and so on, PLC has been widely used in machinery manufacturing, automobile manufacturing, warehouse, machine and tools, textile machinery, packaging machinery, control equipment, power system and electrical machinery industries, as well as chemical, oil, water, sewage treatment, industrial process control product line. It is playing a significant role in the control area.According to the different implementing ways of program instructions, PLC can be divided into the compile type and interpretation type. The Interpretation PLC translates the user program to the intermediate code. Then the PLC running system implements the instructions sentence by sentence, by means of instruction fetching, explaining and performing. This method is relatively intuitive, and easy to implement. However, because each of the implementation of an appropriate instruction should be invoked to explain procedures, it had to spend a lot of time. As it is compiled in the host computer system, the program of compiler-based PLC which is downloaded to the lower computer is capable of immediate implementation without interpretation and can be compiled once but executed many times. Because this mechanism completes the compilation work in the host machine, the program can be loaded and implemented directly, thus it can save a lot of time.In the PLC market of our country, foreign products have high share, especially in the high-end products have been in a monopoly position. Thus, it has strategic importance that the development promotion of PLC product can improve our national manufacturing level and enhance our national competitiveness. After several years of painstaking research, Computer Science Center, high-grade digital laboratory in Shandong Province, independently invented the high-tech products-Shanke SK Series PLC, which has China's own intellectual property rights. The product is now obtaining a good application of the model results in the domestic water, electricity, CNC machinery, medical and health sector. However, the product adopts an interpreted way to implement the instructions, so it is interpreted PLC. It has a series of disadvantages, such as poor portability, slow speed of execution and so on, and this is one of the most important factors of impeding the development of PLC. Aimed at this situation, this paper combines with the national key new product plan-SK Series General PLC technology research, which is undertook by National Engineering Research Center of High-End CNC Shandong Branch, and proposes an approach to design the compiling system of embedded PLC based on ARM. The experiment results show a clear directive development of the SK Series PLC in the process of implementing the instructions and it also can greatly enhance the competitiveness of this product in the market.