Research And Design Of Embedded SoftPLC System Based On Language Transformation

Aiming at the poor scalability of the traditional PLC, in this paper the author proposed an overall design scheme of embedded softPLC system based on language transformation, referring to the IEC61131-3 international general programmable controller programming standards. And every module of the embedded soft PLC system and operation system was designed and implemented.The author first introduces the structure and working principle of traditional PLC. And based on the designing idea traditional PLC, the system structure and working principle of the embedded softPLC were deeply researched. By analyzing the advantages and disadvantages between the Compiled and interpreted mechanism, the author proposed the total design solution for the embedded soft PLC system based on language translation. In addition, the hardware system structures and software system structures were designed.After that, the author elaborated on the concrete realization of the embedded soft PLC system, and the memory variable system, the user program and the instruction explained function library were described separately.Then, based on knowledges about the compiler principles, the author analyzed the process of building the symbol table, and based on this, the lexical analyzer was designed. For the separated and extensible characteristics of XML documents, the author finished the design and realization of translator based on XML. Considering the specific monitoring requirements, the author designed the kvplc communication protocol of application layer , and implemented the protocol on the serial link. Finally, taking the delay-on/off control circuit for instance, verifying the functions of embedded soft PLC was verified.The finally result shows that the embedded software PLC system designed in this paper can achieve some basic control functions and deserves popularization.