Design And Implementation Of Variable Editor Based On IEC61131-3 Standard

After the International Electro-technical Commission promulgated the IEC61131-3 international standard and standardized 5 kinds of PLC programming languages,the integrated development platform supporting multiple PLC programming languages has become the future technology trend in the PLC platform software field.The variable editor conforming to the IEC61131-3 international standard is a key component of the integrated development platform.Its major functions include variable text parsing and memory address allocation.With the in-depth analysis of the contents of the IEC61131-3 international standard,and based on the memory characteristics of PLC equipment,the paper designs a variable editor that conforms to the IEC61131-3 international standard.The main research contents are as follows:1)For parsing the content of variable text specification in the IEC61131-3 international standard,a variable text parsing method combining regular expression and context-free grammar is proposed;2)Base on the memory configuration of PLC equipment,the mapping rules of variables to device memory addresses are formulated.Improved on the traditional optimal adaptation algorithm,the paper proposed a new memory allocation method for the process of assigning memory addresses to PLC variables;3)Implement the variable editor in the Microsoft Visual Studio 2012 environment,develop the data transfer interface between it and other modules in the platform,and design the coexistence function of table editor and text editor,function of text intelligent input prompt;4)Design and implement test cases for each function and stability of the variable editor,and implement system function verification with connecting the PLC device.According to the experimental results,the variable editor has perfect functions and stable operation,and provide correct variable parsing and memory address allocation for the PLC integrated development platform.