The Research And Design Of New Type PLC Programming Software Based On ARM-FPGA

With the continuous development of modern industrial control technology, theapplications of the Programmable Logic Controller, hereinafter referred to as PLC, isincreasingly widespread. Meanwhile, the market has further requirements for the PLClevel, especially in capabilities of continuous process control and system openness, so amore fully functional and open programming software platform is required for matchingthis.This topic was in keeping with this trend and designed a kind of correspondingprogramming software according to the new PLC system mechanism of parallel logicaloperations and pipelined execution instruction, which was based on ARM-FPGA, forprogramming and communicating between program and the new PLC hardware system.A new depth-first recursive scanning algorithm, which was different from the traditionalones, had been proposed. It optimized the spatiality and timeliness itself, which improvedthe speed of the programming of the PLC program as well as the performance of thesoftware.The process of the system development can be divided into two steps as follows;first, it did the requirement analysis and the design of the system structure for the newPLC program software in accordance with the design idea of the software engineering.On the basis of the preceding step, it classified the software into few parts, includingprogram editing module, program compiling module, CAN communicating module andso on, by using the methods of object-oriented and modularization.After modularizing the programming software, it refined the functions of eachmodule. In the program editing module, it built the class hierarchy and component librarymodule object of the ladder diagram first based on the characteristics of the ladderdiagram and the design idea of the object-oriented, then the various derived instructionicons had been used to draw the ladder diagram by the way of graphical input. In theprogram compiling module, in order to realize the conversation from the ladder diagramto the instruction list, few steps should be done. Firstly, it built the structure of logic treeby using the depth-first recursive scanning algorithm. Then, it can obtain the instructionlist after traversing the logic tree with the method of recursive traversal algorithm.Finally，the coding rules based on the new PLC system can converse the instruction listto communication code, which can be running in the PLC hardware. In the CANcommunicating module, the CAN communication protocol had been defined first, thenthe communication between programming software and the PLC hardware platformcould be achieved by the bussing technique based on the CAN. At last, it passed the finalobject code to the terminal machine to achieve the control function according to theestablished protocol format.Result of the experiment shows that the new PLC programming software platform was able to realize the conversion between the program and the communication code,which verified the feasibility of the programming software. Finally, it gave a summaryfor the full text and analyzed the job being continued. Hope that the research can givepromotion of the development of the domestic PLC program software and even the PLCsystem.