Method and system for converting ladder diagram program into instruction list program and compiling instruction list program

Abstract

The invention discloses a method and system for converting a ladder diagram program into an instruction list program and executing compiling and interpretation of the instruction list program. According to the ladder diagram conversion method, energy flow classes and auxiliary nodes are introduced according to the characteristics of edition and execution of a ladder diagram, the class is set on each diagram peak, and an auxiliary node is added; the serial and parallel connection relationship is judged according to the out-degree and in-degree of the class and the auxiliary node where an element is located. After the ladder diagram is converted into the instruction list, a PLC immediate compiling method combined with compiling and interpretation and a divide-and-conquer method concept are adopted, a compiling front end and an interpretation rear end are designed independently, and in combination with a GCC rear-end structure, a PLC compiling system specific to a special machine model is generated. The method and system for converting the ladder diagram program into the instruction list program and compiling the instruction list program have the advantages that the ladder diagram program with a complex logic structure can be accurately and rapidly converted into the instruction list program, and in the conversion process, grammar error checking is carried out on the program, and the common errors like an open circuit, a short circuit and a bridge circuit are excluded, so that the correctness of the generated instruction list program is guaranteed.

Description

technical field [0001] The invention relates to the field of PLC control systems, in particular to a method for converting a PLC ladder diagram program into an instruction list program and compiling and executing the same. Background technique [0002] Both ladder diagram and instruction list are commonly used programming languages ​​for embedded soft PLC. The ladder diagram programming language is developed and evolved on the basis of the control principles of contactors and relays commonly used in electrical control systems. Because it is very similar to the electrical operation control circuit diagram, it is intuitive and corresponding, and easy to learn and understand. , which is familiar and loved by the majority of electrical engineers. The instruction list programming language is a programming language similar to assembly language using mnemonics for programming. It is composed of operation codes and operands. It uses a series of mnemonic symbols composed of operatio...

AI Technical Summary

Problems solved by technology

C language constructs a variety of grammatical forms and a small number of keywords to achieve complex and changeable functions. This point is inconsistent between PLC and C language. The two language styles are very different, so it is not suitable for conversion

At the same time, such systems are highly dependent and are easily affected by other factors, such as C compilers.

It is difficult to maintain and upgrade in the later period, and it is inconvenient to expand functions. The conversion process needs to be restructured, which can easily cause new problems

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