Design And Implementation Of Measurement And Control System Of Enthalpy Difference Laboratory

More and more high sealing construction materials used in modern buildings, and in-room air pollution is becoming more and more serious. Therefore, the fresh air ventilation system is more and more popular. Generally, the performance parameters of air conditioning products are tested and calculated by enthalpy difference laboratory. The common enthalpy difference chamber can not be used to test the performance of fresh air ventilator. So, it is necessary to construct the enthalpy difference Laboratory for the testing of fresh air ventilator. The performance of measurement and control system has a direct impact on the reliability and accuracy of the experimental data, and the superior performance of the measurement and control system makes the scientific research activities more convenient and effective.In this paper, the construction of the Institute of thermal energy in the enthalpy difference laboratory project is used as a platform to research, practice and economy, meanwhile the measurement and control system of enthalpy difference chamber is studied and designed. Analysis and research on the principle and structure are used for the energy recovery enthalpy difference chamber, analysis and design of the architecture system of the measurement and control system are according to the characteristics of the laboratory. Through the analysis of system functional requirements, the software and hardware of the controller are designed. And using LabVIEW to develop the PC software.The application program of the controller is designed by using the multi-threading program design idea, which is based on the embedded Linux operating system. The use of threads increases the efficiency and reliability of the program.According to the characteristics of the CAN and Modbus protocol, the communication protocol is designed for the communication between the embedded controller and the host computer.Through the analysis of the laboratory temperature control model, analysis and comparison of the existing control algorithms, paper puts forward to use the fuzzy-PID control algorithm as the main control algorithm. By comparing the simulation results of common PID and fuzzy-PID, the superiority of the fuzzy-PID algorithm and the correctness of the algorithm selection can be seen.This paper is based on ARM9 as the hardware foundation. The design of the application software and the design of the fuzzy control algorithm are embedded in the Linux operating system platform. The design of measurement and control system of enthalpy difference chamber is realized with the Labview host computer software. It provides an efficient, reliable, convenient and economical solution for the measurement and control system, which has important significance for the popularization and application of the system plan and scientific research.