Application Research For Three-dimensional Virtual Logistics Production Line By Using Soft PLC Technology

Soft PLC technology is a new type of control technology emerging gradually in the international control field.Compared with traditional PLC,soft PLC has the advantages of openness,and good expansibility etc.Logistics production line has the advantages of high efficiency,convenient use and low cost,and it has been widely used in industrial production.However,the application of soft PLC technology in logistics production line is not common.Based on this situation and combined with the finished product logistics production line of a cigarette factory,the application research of soft PLC technology in three-dimensional virtual logistics production line was carried out.Through research and development of a logistics production line training system based on soft PLC,the system can be used for PLC programming training PLC simulation research on logistics production line control and logistics production line operation demonstration.The requirement of the soft PLC programming system are analyzed and it is determined that the programming system has ladder diagram drawing,ladder diagram modification,ladder diagram grammar and logic checking,ladder diagram to instruction list compilation and conversion,ladder diagram saving and loading and other function.The soft PLC editing interface is designed by Microsoft Foundation Classes multi-document application program,which separates the management and display of program data structure and improves the development efficiency.The drawing area of ladder diagram adopts grid design,and the graphic elements of ladder diagram are designed by classes to improve the development efficiency.The storage of ladder diagram is implimented with double linked list,which can meet the requirements of dynamic editing of ladder diagram.Ladder diagram grammar and logic checking functions are realized throught the establishment of grammar rule base.By comparing the three common conversion algorithms for converting ladder diagram to instruction list,including topology sorting,logic tree and binary directed graph,their defects are analyzed,and a series-parallel conversion algorithm is introduced.The ladder diagram is mapped to AOV diagram,and a logic tree is established by using serial-parallel scanning.The instruction list is generated by traversing the logic tree to complete the conversion from ladder diagram to instruction list.The system structure and process flow of finished product logistics production line in cigarette factory are analyzed,and the control program of logistics production line is designed.SolidWorks software is used to model and assemble the logistics production line,and the object of logistics production line simulation is built.EON Studio is selected as the development platform for virtual realization of logistics production line,and the loading of production line model,model collision detection and dynamic realization of model are completed in EON Studio,thus realizing the construction of three-dimensional virtual scene of logistics production line.Setting PLC input and output port information and behavior script files of each virtual equipment of the logistics production line are configured to generate a PLC control port information list of the three-dimensional virtual logistics production line,and realizing data communication between the soft PLC and the three-dimensional logistics production line is realized through a control mode.The development of logistics production line training system based on soft PLC was completed,and a virtual finished product logistics production line was constructed.The ladder diagram program was written to realize the process control of transportation,sorting,detection,storage and generation of the logistics production line,and the operation display of the virtual production line for finished product logistics was completed,which verified the effectiveness of the system.