Design Of The Temperature Adjusting And Humidity Control System Ofthe Climate Chamber For Furniture VOC Detection

Climate chamber,as an effective measure of non-destructive testing equipment,has been widely used to detect volatile organic compounds(VOC)emission from furniture.It can provide a stability testing environment based constant temperature,relative humidity,air velocity and air change rate.Temperature and humidity control system is the core component of the climate chamber.However,the control algorithm as well as the coupling effects of temperature and humidity of lead to many problems(such as low application of software,excessive requirement to precision).In this paper,an improved temperature and humidity control system was designed.The main achievements and work content is as follows:(1)The sectional control strategy applied PID arithmetic was used to detect temperature.The dew-point humidity control theory was used to avoid coupling effect of temperature and humidity control synchronously and improve stability,precision of the system.That can transform the relative humidity control in environmental chamber into one of the temperature controls in the water tank.(2)The design,device and hardware selection of temperature and humidity control system and dew-point humidity was carried.Based on SIMATIC S7-200 series PLC software programming and system verification were completed to better satisfies the requirement of national standard.