农作物喷灌控制系统毕业设计（已处理）.doc

唐 山 学 院 毕 业 设 计 设计题目 农作物喷灌控制系统设计 系 别 机电工程系 班 级 07测控技术与仪器 2 班 姓　 　名 李 娟 指 导 教 师 杨旭东 2011年6月1 日农作物喷灌控制系统设计 摘 要 本论文首先对我国农业用水情况进行了分析介绍了农作物喷灌控制系统的现状本设计中利用三菱FX2N系列的PLC作为控制设备用其自带的PID功能指令通过变频调速实现系统对农作物喷灌的自动控制该系统可在无人或半无人干预下自动运行该系统将大大提提高水资源的利用率节省大量人力物力并为我国实现农业现代化地发展做贡献 喷灌系统中灌区用水量是变化的用水量变化时会引起喷头工作不稳定喷灌效果会受到很大影响本系统结合工程实例采用变频器控制水泵电机转速实现了恒压供水大大提高了喷灌效果论文中详细论述了变频调速恒压供水系统原理对系统的主电路设计硬件选择和软件设计进行了详细阐述本系统可通过组态软件控制参数的设定数据处理实时监测报警等任务自动化程度很高 本文中介绍了电动机调速技术的发展和现状对喷灌系统的电机交流变频调速系统的方案进行了论证其次介绍了交流异步电动机的变频调速原理和电压正弦脉宽调制波 SPWM 的微机算法再次介绍了PLC的基本组成和各部分的作用及PLC的工作原理最后介绍了系统的工作流程系统的电气结构硬件配置和软件实现应用表明系统实现简单操作方便运行稳定可靠且具有较好的节能效果 关键词PLC PID 恒压供水 自动喷灌 组态软件 The Design of Control System for the Farm Crop Irrigation Abstract At first the present situation of the auto control of the farm crop irrigation was analyzed in this paper The FX2N PLC of Mitsubishi was used as the control equipment of this new system and at the same timePID function of its own to carry out the auto control of the farm crop irrigation The utilization rate of water resources by the control system of the farm crop irrigation according to the PLC was enhanced and the design contributes to carry out the mode In view of the instability of the Sprinkler Irrigation System affected by the water requirement within the operation areacombined with engineering examplea water supply system with constant pressure through applying PLC and transducer in greenhouse is proposed in this paperThe schematic diagram of the frequency controlincluding the design of main circuit and software for the system is presentedThe systemwhich is composed of host computerPLCtransducerpressure transmitterand motor-pump system Firstly this design not only introduces the development and current situation of electromotor regulating technology but also discusses the schemes of the indirect Current Frequency Control regulation system of the Mercering machine Second