摘要
粮食储藏是国家为防备战争、荒灾以及其他突发性事件而采取的有效措施。粮食是人类生存的必需品，温度与湿度是保存好粮食的先决条件，随着中国加入WTO和粮食市场的逐渐开放，储存大量的粮食对稳定国民经济的发展起到至关重要的作用。影响粮食安全储藏主要参数是粮食的湿度和温度，这两者之间是互相关联的。人们通常使用温度计、湿度计来测量粮库的温度和湿度，通过人工加热、加湿、通风和降温等方法来控制粮库的温度、湿度，这种方法不但控制精度低、实时性差，而且操作人员的劳动强度大。同时温度与相对湿度的大幅度变化可能导致种子大范围腐烂或者影响种子的发芽率，从而带来极大地经济及财产损失。因此，保证适宜的粮库温度、湿度对保证农产品种子存储质量十分重要。模块化设计的目的
本设计分为上下两层结构，下位机系统以ATMEL公司生产的AT89C51单片机作为温、湿度监控核心部件，采用DS18B20温度传感器，它是数字温度传感器，能够直接读取被测物的温度值；选取HS1101作为湿度传感器，通过将该湿敏电容置于555定时器与电阻组成的电路中，将电容值的变化转为与之呈反比的电压频率信号，并采用RS485与上位机进行通信；一旦温度或湿度值超过设定阈值，即可实现报警。上位机系统仍以单片机为核心，扩展数据存储器，在键
盘模块里可以更改阈值，LCD显示模块显示从下位单片机传来的温度、湿度值。从而实现一种小型粮库的温湿度智能监控。实验表明该系统具有转换速度快、精度高、控制能力强等特点。
目前实现粮库温湿度的智能控制需要一种稳定性高、成本低的温湿度智能控制系统，其采用上、下位机控制结构，实现全方位智能化的粮库监控。单片机在这种系统中往往作为一个终端机，安装在系统的某些节点上，对现场温湿度进行实时的测量和控制。单片机的高可靠性和强抗干扰能力，使它可以置于恶劣环境的前端工作。
关键词 单片机；小型粮库；温度；湿度
Abstract
The food storage is the national guard against war, for Huang zai and other unexpected events and take effective measures. Food is the human survival necessities, temperature and humidity is to keep the good food prerequisites, with China's accession to the WTO and the opening up of the food market, store large amounts of food to stabilizing the develo
pment of national economy play a crucial role. Affect food security is the main parameters of grain storage humidity and temperature, between the two are interrelated. People often use thermometer, island-from mosquitoes to measure the temperature and humidity of warehouse, through the artificial heating, add wet, ventilation and cooling method to control the warehouse temperature, humidity, this method not only control precision low, real-time, and operation of the personnel labor intensity. At the same time temperature and relative humidity can lead to big large variation seed range decay or influence of seed germination rate, thus brings great economic and property losses. Therefore, ensure the warehouse of the appropriate temperature and humidity on agricultural seed storage quality guarantee is very important.
This design is divided into the upper and lower levels structure, lower place machine system to ATMEL company produces the AT89C51 as humidity and temperature monitoring core components, the temperature sensor DS18B20, it USES "single bus" interface, can be measured directly read things value; Select HS1101 as humidity sensor, through the wet sensitive capacitance in 555 timer and resistors circuit, will the change of capacitance valu
es to the inverse of a voltage and frequency signal, and USES the RS485 communication and the upper machine;Once the temperature or humidity value more than setting threshold, can realize the alarm. PC system based on single-chip microcomputer is still, extended data storage in the keyboard module can change the threshold, LCD display module from a single chip that under the temperature, humidity value from. So as to achieve a small the temperature and humidity of the warehouse intelligent monitoring. Experiments show that the system has a conversion speed and precision, strong ability to control etc. Characteristics.
Now realize intelligent control of the temperature and humidity warehouse need a high stability, low cost of temperature, humidity intelligent control system, and its use,under a machine control structure, achieving all-round intelligent warehouse management control system.SCM in such systems often as a terminal, installed in the system of some nodes, the temperature and humidity of real-time measurement and control. The single chip microcomputer high reliability and strong anti-interference ability, make it can be placed in the front of the bad environment.
Key words :single-chip microcomputer; Small grain depot; Temperature; humidity