Design Of Process Control Experimental Platform And Development Of Experimental Contents

Process control is an important course of automation and relevant professions,and attaches equal importance to the theory and practice.In order to master the content of the process control course,the experiment is an essential part in teaching process.However,the imperfect experimental system caused the formalization in process control experimental teaching and students didn’t have a deep understanding of the experiment.Therefore,the design and development of a process control experiment platform with superior performance and perfect function is of great significance in terms of improving the quality of experimental teaching and cultivating students’ ability of engineering practice.Funded by the project of key science and technology innovation team in Shaanxi province,the study of building a set of process control experimental platform which combines physical experiments with semi-physical simulation experiments and developing the experimental contents is carried out in this thesis.The main work is presented as follows.Ⅰ.Hardware and software design of the process control experimental platformAccording to the requirements analysis of process control experimental platform,a process control experimental platform based on S7-300 PLC is designed.In terms of hardware part,a miniaturized three-tank experimental equipment with multiparameters is designed to simulate the typical processes,such as first order process,second order process and large time delay process.Taking the experimental equipment as controlled object,the hardware of control system is designed,including counting the control points,selecting components,designing and making control cabinet and MCC cabinet,etc.In terms of software part,experimental content programs based on STEP7 are developed and debugged.Monitoring interface based on WinCC is designed.The upper machine communicates with lower machine by Ethernet.Ⅱ.Development of physical experimental contentsAccording to the experimental content requirements of process control course,physical experiments are designed on the experimental platform.Four kinds of process parameters are measured and controlled,including level,temperature,flow and pressure.Simple control experiments are designed,such as modeling experiments and single loop control experiments.Complex control experiments are designed,such as level cascade experiment and flow ratio control experiment.And the design scheme,testing results and instructions of each experiment are given.Furthermore,taking ant colony algorithm as an example,the experimental verification method for intelligent algorithm on the experimental platform is demonstrated.Ⅲ.Development of semi-physical experimental contentsAccording to the principle and features of the semi-physical simulation,the semi-physical simulation based on MATLAB and Win CC is implemented.The data between MATLAB and WinCC is exchanged by OPC technology.To make the experiment platform more compact,MATLAB is integrated into the WinCC interface through C script.The single loop level control and level cascade control semi-physical simulation experimental contents are designed to verify the feasibility of the scheme.Under the condition of the same control parameters and the same controlled object,the similarities and differences between physical experiments and semi-physical simulation experiments are compared and the reasons are analyzed.The experimental platform combines physical experiment with simulation experiment.The same experiment is presented in different ways,which can deepen students’ understanding of the course.The introduction of MATLAB can reduce programming difficulty and improve students’ autonomy for designing experiments and openness of the experimental platform.In addition,the experiment platform can provide a convenient verification method for the advanced theoretical works.