Design And Development Of Experimental Platform Software Of The Cascade Control System For Air Heating Mixing Process

Cascade control which is widely used in the industrial process is one of the important and difficult points in the course of automation process control.How to help students to deepen the understanding of cascade control in the industrial context is an important problem to be solved in the course of the process control.Supported by the construction project of Liaoning Metallurgical Comprehensive Automation Engineering Laboratory,choosing air heating mixing process which is common in the industrial process as the object,this paper has completed the design and development of experimental platform software of the cascade control system for air heating mixing process,establishing a cascade control experimental platform which is highly consistent with the industrial environment for process control course teaching.The main works of this paper are as follows:(1)Based on the detailed review of the development situation of the existing process control experimental teaching platform,choosing air mixing process as the controlled object,from the goal of the assistance for teaching experiment,this paper does a demand analysis to the experimental platform of cascade control system in detail.(2)This paper designs the overall architecture of the experimental platform software of the cascade control system for air heating mixing process,which is composed of PLC process control software,monitoring software and model software,in which PLC process control software and monitoring software complete the single loop control,cascade control and dynamic step response experiment in industrial environment,and based on the dynamic experimental data,model software complete the process identification and single-loop and cascade controller parameter tuning by the way of human-computer interaction.(3)Based on Siemens S7-300 PLC control system architecture,experimental platform software of the cascade control system for air heating mixing process was completed,using STEP 7 software to develop PLC process control software,using WinCC SIMATIC software development monitoring software,based on GUI MATLAB(graphical user interface)developing a model software,and realizing the data communication between the monitoring software and the model software by OPC.(4)In this experimental platform,the experimental verification of identification,conventional PID control and cascade control is carried out.The results show that the platform has a high degree of simulation of industrial field environment,intuitive and easy to understand,convenient and flexible advantages,which has played certain role in promoting the reform of the process control teaching.