Design Of Temperature Control System For Large-scale Basic Environment Simulation Laboratory Based On PLC

The design and manufacture of large aircraft in China have been developing rapidly in recent years.In order to ensure the reliability of the equipment design and the adaptability to all kinds of climate,the environmental adaptability test must be carried out before it is put into mass production.In order to save manpower,material and financial resources,it is necessary to build a large-scale environmental simulation laboratory to simulate the possible climatic conditions of the aircraft in the laboratory.This paper takes a large project based environmental simulation laboratory as the background,based on PLC and combined with WinCC is designed based on environmental simulation laboratory control system,and the environment of the indoor temperature control part is studied as the object.This paper is based on a large basic environment simulation laboratory project,designed the control system based on PLC and WinCC,and the temperature control of big chamber was studied.The large basic environmental simulation test system composed of large environmental chamber,small environmental chamber,cooling water system,the cooling load system and hot wind circulation system.Realize high and low temperature,rain,ice,snow and other climate simulation through the coordinated control of each subsystem operation.Firstly,this paper analyzes the overall process flow of the system according to the overall structure of the control system,the overall scheme of the basic environment simulation control system is designed combined with the technical requirements and functional requirements.Secondly,The hardware and software design of each subsystem and centralized control system were completed by the use of SIEMENS S7-300 series PLC.Then,the mathematical model of the surface air cooler,the mixed flow section of the valve and the temperature of the large environmental chamber were established base on mechanism method.The single loop control,cascade control and cascade fuzzy PID control were simulated in MATLAB/Simulink,and the fuzzy PID cascade control is used to simulate the typical test flow.The fuzzy PID control algorithm is realized in Step7.Finally,the design and implementation of the monitoring and control system software based on WinCC is used for the on-line monitoring of the control system.