摘 要
传统的灌溉模式自动化程度极低，基本上属粗放的人工操作，即便对于给定的量，在操作中也无法进行有效的控制，为了提高灌溉效率，缩短劳动时间和节约水资源，必须发展节水灌溉控制技术。现代智能型变频器是进行农田自动灌溉系统田间管理的有效手段和工具，它可提高操作准确性，有利于灌溉过程的科学管理，降低对操作者本身素质的要求。除了能大大减少劳动量，更重要的是它能准确、定时、定量、高效地给作物自动补充分，以提高产量、质量，节水、节能。我国是一个水资源缺乏的国家，人均水资源量仅为世界平均水平的1/4；同时我国又是一个农业大国，农业用水量约占总用水量的70%左右。
该系统主要由主控PLC、采集器、各类传感器(水分传感器、降水量等)、电缆线、电磁阀、田间微型测量站(大气温度、大气相对湿度、风速、风向、降水量、蒸发量)、控制箱、机井、水泵、主管道、支管、毛管等构成。利用PLC具有速度快，功能强，体积小，功耗低，使用方便，性能可靠，成本小的优势。设计出具有小键盘，数码显示部分器件，在功能上具数据的采集、自动控制、运行监视、报警、运行管理的功能的嵌入式系统，使该系统适宜于各种作物，土壤，气候，地质的相关操作。各类传感器采集的信息传至A/D转换器，再传至PLC处理对比，PLC决定此时是否灌溉，同时实时显示当前土壤湿度。
关 键 词：农田；PLC；自动灌溉；控制系统
ABSTRACT
The traditional irrigation mode has a very low degree of automation and is basically a extensive manual operation. Even for a given quantity, it cannot be effectively controlled in operation. In order to improve irrigation efficiency, shorten labor time and save water resources, Water-saving irrigation control technology must be developed. Modern intelligent controller is an effective means and tool for irrigation system field management. It can improve the accuracy of operation, benefit the scientific management of irrigation process, and reduce the requirement of the operator's own quality. In addition to greatly reducing the amount of labor, more importantly, it can accurately, regularly, quantitatively, efficiently and automatically replenish crops to improve yield, quality, and efficiency. Water, energy saving. Our country is short of water resources, the per capita water resource quantity is only 1 / 4 of the world average level, at the same time, our country is a big agricultural country, the agricultural water consumption accounts for about 70% of the total water consumption.
The system consists of PLC, collector, sensor (water sensor, precipitation, etc.), cable, solenoid valve, field micro measuring station (atmospheric temperature, relative humidity, wind speed, wind direction, precipitation, evaporation, control box, etc.) Machine well, pump, main pipe, branch pipe, capillary tube and so on. The use of PLC has the advantages of high speed, strong function, small volume, low power consumption, convenient use, reliable performance and low cost. An embedded system with the functions of small keyboard, digital display, data acquisition, automatic control, operation monitoring, alarm and operation management is designed. Suitable for all kinds of crops, soil, climate, geological operations. The information collected by all kinds of sensors is transmitted to the A / D converter, and then to the PLC processing to determine whether to irrigate at this time, and to display the current soil moisture in real time.
Key words: orchard; PLC; automatic irrigation; control system
目 录
1 绪论 1
1.1 课题背景及意义 1
1.2 国内外研究现状 1
1.2.1 国外研究现状 1
1.2.2 国内发展现状 2
1.2.3 研究主要内容 2
2 农田自动灌溉系统总体方案 3
2.1 总体设计 3
2.1.1 灌溉综述 3
2.1.2 系统主要功能 3
2.2 系统运行结构图 3
2.3 系统运行方式 4
3 农田自动灌溉系统硬件设计 5
3.1 系统硬件的设计原则 5
3.2 变频器的确定 6
3.3 系统的组成 7
3.3.1 设备确定 7
3.3.2 PLC输入/输出点分配 8
3.3.3 电机启动 9
4 软件设计 10
4.1 设计方法 10
4.2 设计原则 10
4.3 系统功能的设计 11
4.3.1 灌溉流程设计 11
4.3.2 电机启动设计 19
5 PLC的调试与程序的仿真 20
5.1 PLC控制的安装与布线 20
5.2 程序的仿真 21
6 结论与展望 25
致 谢 26
参考文献 27
附录 28
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