Design And Imolementation Of PID Control System Based On Soft-PLC

In recent years, the computer is used more and more widely in industrialcontrol.The remarkable results of scientific research and application are made inhigh-precision servo control and the compute integrated manufacturing. Theprogrammable logic controller is the outcome of the microelectronics technology andthe automatic control techniques.It is a kind of special computer using incontrolling.And it is used widely in the mechnical manufacturing,industrialcontrol,power and transportation field. The late20th90years,for overcome theshortcomings that the traditional PLC hardware architetureis is not open,the variousmanufacturers of PLC programming is not uniform,the soft PLC technology comes out.The PID controller is a closed-loop control system. Because of the PID controlleris simple in form and fixed, it can keep better robustness in a very wide range ofoperation.Meanwhile,the engineering and technical personnel can regulate the system ina simple and direct way.Therefore, the PID controller is used in a wide range ofapplications.In this paper,the soft PLC architecture system which is open and developed by theShenyang Golding NC Tech Co,Ltd, Shenyang. The D/A output, the PWN input and theencoder input interface of the servo motor are added to the hardware structure of thesoft PLC. Aim at the shortage of the ARM7microprocessor ships which can’t deal withthe floating-point, the operation program that the integer simulates the floating point isprogrammed. Even, the program is used in the soft PLC system which made the softPLC has the capability to calculate the floating point. The development and theapplication of the PID control technology is exponded. The PID control algorithm isanalysed and researched. The PID function module is designed and embedded into thesoft PLC system. The PID control function of the soft PLD is achieved. The parameterssetting of the PID is researched. The work to set the PID parameters is finished usingthe critical proportion method and collect test method by simulation and the livedebugging. The experience of setting the parameters is accumulated. The expandabilityof the PID control function of the soft PLD is improved.