Research And Implemention Of Soft PLC’s Upper Computer Programming System Integrated With Motion Control Function

The traditional control system which combines hard PLC and motion controller has somelimitations on complex and scalable characteristics of the configuration. Therefore, the paper proposesa control scheme of integrating motion control functions and soft PLC system through softwareintelligence based on the analyzing of the Soft PLC technology and the standard of PLCopen.Thecontrol system is divided into two parts, i.e., the upper and lower subsystems. The editing andcompiling module of the upper subsystem are designed. In addition, a soft PLC’s upper computerprogramming system is developed based on the standard of IEC61131-3and PLCopen.The system’s editing module is firstly designed. Ladder diagram and instruction list, which arecommonly used in PLC, are chosen as the logic control programming language, and PLCopenstandard motion control module as the motion control programming language, and thus a graphicallanguage editing environment is designed to support design and edit operation of the two graphicallanguages. In addition, an instruction list programming environment supporting editing of theinstruction list program is also designed, which is capable of transforming the instruction list to aladder diagram.The compiling module of the system is then discussed. An instruction list is used as anintermediate language to achieve transition from ladder diagram to object code. The same compilingstrategy is used in the motion control module. The corresponding object code of logic controlinstructions and motion control IL order set are also designed. Among the process transition fromladder diagram to instruction list is based on the AOV graph and logic tree. The ladder diagramproduces object code during the process of the transition, which is unnecessary to solely handle theinstruction list to produce the object code, thus the process is simplified.At last, experiment shows that not only this system is feasible in logic and motion controlprogram editing, but also the structure of motion control program edited using PLCopen motioncontrol module is simple and memory-efficient.