Temperature Control System Of Vegetable Greenhouses

The Author conducted a survey on the status of vegetable greenhouse in Shouguang.He founds that most of the vegetable greenhouse operation based on a single family. As the high economic cost,the multi-parameter intelligent control device is not widely used. The purpose of this task is to select the temperature as the control object, to study a kind of Automatic Control Equipment which can instead of manual operation with low economic costs.The temperature measurement accuracy of the temperature control system is±0.5℃;It's display accuracy is 0.1℃; It's temperature setting range is 0℃～+50℃.The temperature control system of the vegetable greenhouse including both hardware design and software design.Hardware design includs temperature sensing circuit,clock circuit,LCD display circuit,alarm circuit,strong electric control and driver circuit, etc.The temperature detection devices uses a single-bus digital temperature sensor DS18B20; clock chip select DS1302; LCD module uses HG1286401C; strong electrical control and drive circuit uses MOC3061,with can isolate strong electricity and weak electricity. Software design uses modular programming, which developed by C language.The DS1302, HG1286401C are initialized At initial power,it reads the second signal for the first time,at the sime time the time and temperature information,such as year, date, hour, minute is read processed and shown. Then the system Compared the temperature value with the temperature limited,determining the temperature exceeded the upper or lower limits.If the temperature is more limited, the heating or ventilation equipment are started, and also sound an alarm in order to achieve temperature control.The author uses one I/O port with one DS18B20, accessing three DS18B20 in total,which can control. three vegetable greenhouses. The biggest advantage of the approach is that it eliminates DS18B20 matching serial number and alarm search procedure, so that programmers have become more simple. In addition, when the DS18B20 damaged, it can be directly replaced, which made the maintenance easier.The temperature control system for the vegetable greenhouse is simple, accurate and reliable.lt can be used for the temperature control of vegetable greenhouse,and also can be used for rain storage, cold storage and other occasions.