Study On Automatic Control System Of Radiant Air-Conditioning Test Stand Based On LabVIEW

LabVIEW (Laboratory Virtual Instrument Engineering Workbench) is created by a company NI (National Instrument) in U.S. A with icons instead of lines of text to create applications for graphical programming language. It has been widely used in industrial and laboratory data acquisition and instrument control. In this paper, control software of data a cquisition and radiation a ir-conditioning c ontrol s ystem is programmed w ith LabVIEW. T he software i s i ntegrated t emperature, h umidity, pressure, carbon dioxide and other on-site thermal parameters of the acquisition and display. It is two-way electrical valve or three-way electrical valve which achieves the laboratory t est room t emperature, humidity, supply and return water pressure a nd backwater t emperature co ntrol. This achieves the a utomation of the r adiant air-conditioning test system, and meets the requirements of the control for system.The control of radiant floor air-conditioning, because it is a typical time delay controlled object, it has not been well resolved for a long time. Basing on study of general PID control u sed on the floor air-conditioning and w ith sampling control methods, this problem is discussed and some interested data is obtained with a better control effect.The bench room temperature detected by a digital serial communication(l-wire bus) with the chip temperature sensor, this temperature measurement system only need a se rial interface cable can take tens to h undreds of sensors, greatly reduced on-site connection, but also greatly improve the measurement accuracy. In this paper, such a measurement system connects with database, and communications between Excel and LabVIEW and other issues are deeply discussed.The application prospects of LabVIEW in the field of HVAC control system and a number of issues calls for solution are discussed.