Study And Design Of Temperature And Humidity Intelligent Detection Technology And Unit For Cold Storage Space

As the most populous country in the world, the consumption of food is very high in China. Therefore the demand of agricultural products is great. However, agricultural products’ regionalism, seasonality and perishability take themselves very strong influence. But people’s demand for agricultural products doesn’t change as the regional and seasonal differences. Low temperature can inhibit the respiration intensity of agricultural products and the growth of bacteria, therefore it can reduce the wastage of agricultural products in the low temperature. In order to solve those problems above, we need to put agricultural products in cold storage space for fresh-keeping. Temperature and humidity are the two extremely important monitoring indicators in the cold storage space of agricultural products. In order to get the expected effect on freshness, the temperature and humidity of agricultural products’storage space must be strictly controlled in the optimum scope for agricultural products’fresh-keeping. Otherwise the temperature and humidity will directly affect the quality of agricultural products’fresh-keeping. According to the needs of detection for temperature and humidity in cold storage space, this paper put forward a set of solutions about intelligent temperature and humidity detection system which is based on RS-485 and communication protocol of Modbus. Besides, this paper also refers to the detailed design and development of the software and hardware which are related to the above mentioned solution scheme.This intelligent temperature and humidity detection system consists of three parts: intelligent sensor unit of temperature and humidity, detection unit, and upper computer. In the intelligent temperature and humidity detection system, the main duty and responsibility of the intelligent sensor unit of temperature and humidity is detecting environment’s temperature and humidity and processing the data gathered from sensitive element. The main duty and responsibility of detection unit is to realize the network communication. And a serial communication interface is designed on detection unit which is based on RS-485 and communication protocol of Modbus. When receiving the request for measuring temperature and humidity from the master, detection unit upload data gathered from the sensor unit to master in time. The main duty and responsibility of upper computer in this system is data query, data analysis, and display. This paper refers to the detailed design and development of the software and hardware, and takes calibration for the intelligent sensor unit of temperature and humidity. This intelligent temperature and humidity detection system is tested in GDWJS which can simulate the low temperature and high humidity environment of cold storage space for keeping agricultural products fresh.Through the result of the test in the laboratory environment and GDWJS, we can draw a conclusion that this intelligent temperature and humidity detection system works well. And it can detect temperature and humidity in the environment in real time. After calibration, the temperature and humidity detection system can detect the temperature and humidity in environment more accurately, thus providing the basis for upper computer to make better control decision.