Research On Control System For Pillow-style Packing Machine Based On Embedded Soft PLC

Traditional PLC has always been the major driving force in the field of industrialcontrolling, but the closure of the PLC and its compatibility become the key causes ofrestrictions on PLC further development, with the formulation and implementation ofthe IEC61131standard, a new control technology~software PLC is getting a rapiddevelopment. At the same time, because of many advantages of embedded system hasbeen widely used in the industrial field, so the combination of soft PLC and embeddedsystem will be the inevitable choice.Based on the situation of the embedded soft PLC industry allover the world, thedevelopment system, operation system and the issues of real-time in software systemhave been studied in this dissertation. The main contents are as following:(1)The structure and working principle of the traditional PLC are studied. Thearchitecture of the embedded soft PLC is established, combined with theoreticalknowledge of embedded systems. The related functions in this system are identified.(2)The development system of embedded soft PLC is studied. The ladder as PLCprogramming languages is selected, and the edit and compile function of the ladder arerealized in the VC6.0programming environment of the PC. The function which cansuccessfully turn ladder diagram into instruction list code and further into object codeare also realized.(3)The running system of embedded soft PLC is studied. The Mini2440learningboard of the Friendly arm is selected as hardware platform, and the Linux operationsystem is chosen as software environment. The Linux kernel and root file system aretransplanted, in order to build the embedded Linux software environment. Thefunctionality of the instruction in the operation system executed is completed.(4)The motor rotating model in embedded soft PLC system is established. Themotor is controlled by using the PWM function in S3c2440chip timers, and thefeasibility and accuracy of the entire system are verified. The design requirements thatthe system design is reliable, the response is fast are conformed.(5)The reasons for lack of real-time in the Linux system are explored, the methodof based on Xenomai and Linux dual-core are proposed. The real-time modification arecarried, and transplanted to the ARM platform. The real-time environment of runningsystem in the embedded soft PLC system is realized.