Design And Development Of A Control Device For Fresh Vegetables Preservation In The Crypt Test Storehouse

Storage and preservation of vegetables is not only an important step for promoting vegetable production and processing,but also an important way for increasing the incomes of the majority of vegetable farmers.Compared with developed countries,there are several problems in the vegetable storage and preservation industry of China,including slow development,high cost,large investment in equipment and human resources.Therefore,it is necessary to develop a high level and high quality vegetable storage and preservation technology.The storage of the cellar is the vegetable storage method commonly used by the majority of peasants.A new technology is required in order to change the management mode of cellar storage mostly based on artificial experience,maximize the vegetable storage period in rural areas,and reduce the vegetable loss rate.Hence,this paper developed a set of vegetable preservation control device suitable for rural use.This study implements the programmable control(PLC)technology,configuration monitoring technology,wireless network technology,and sensor technology to develop a fresh-keeping regulation and control device for vegetable crypts.In this paper,according to the characteristics of environmental control in the crypt,the ZigBee wireless network technology is used to realize the automatic detection and control of the temperature and humidity in the cellar.The design of the control system hardware includes S7-200PLC,expansion modules,temperature&humidity sensors,and the implementation of control equipment.The PLC is used as the system's main controller.The temperature and humidity sensors and oxygen detectors are used to measure the temperature,humidity,and other indoor environmental parameters inside the crypts.Through the implementation of control equipment heat pump system,fans,humidifiers,the temperature and humidity adjustment is realized in the crypt.The software for the device of freshness preservation of vegetables includes PC monitoring software and PLC software.The host computer software realizes long-distance monitoring of the system,realizes the real-time monitoring of temperature,humidity and oxygen concentration in the crypt.Beside,this system has the functions of real-time data and historical data display,online modification of real-time control parameters.The PLC software is mainly used for control system program design based on the ladder diagram.The device of freshness preservation of vegetables in the crypt regulation after debugging and running can meet a variety of vegetable storage requirements by controlling environmental temperature and humidity.This system has the advantages of simple operation,stable operation,strong applicability,and good interface besides good configuration monitoring and remote control.The lowest temperature is up to 0 ? and the operational temperature can be maintained at 0-5 ?.The humidity is up to 95%and can be maintained at 85%-95%.Moreover,this device reduces the temperature and humidity fluctuations.The device can adapt to the storage requirements and development trend of modern agricultural products,and this technology has a wide application prospect.