【作者】 张艳；

【导师】 王炳乐；

【作者基本信息】 重庆大学 ， 机械工程， 2007， 硕士

【摘要】 本论文论述了自动化技术在灌溉管理中的重要性,详细介绍了国外及国内自动化技术在灌溉中的应用现状及存在的问题,并对节水灌溉控制技术的发展趋势进行了探讨。根据喷灌管网的供水要求,设计了一套由PLC、变频器、远程压力表、两台水泵机组、计算机、通信模块等主要设备构成的全自动变频恒压供水系统,具有全自动变频恒压运行、自动工频运行、远程手动控制和现场手动控制等功能。系统有效地解决了传统供水方式中存在的问题,并具有多种辅助功能,增强了系统的可靠性。并和计算机实现了有机的结合,提升了系统的总体性能。以供水系统的扬程特性、管阻特性为基础,分析并比较了采取变频调速方式实现恒压供水与传统的阀门控制恒压供水方式的节能机理。通过对变频器内置PID模块参数的预置,利用远传压力表的水压反馈量,构成闭环系统,根据用水量的变化,采取PID调节方式,在全流量范围内利用变频泵的连续调节和工频泵的分级调节相结合,实现恒压供水且有效节能。论文提出了采用两台水泵分级控制,轮流变频启动的控制策略,分析了两泵供水方式的各种供水状态及转换条件。对电机由变频转工频运行方式的切换过程,给出了具体的切换方法和控制电路。通过对计算机和PLC之间通信协议的研究,完成了上、下位机的通信设置,开发了计算机监控程序,实现喷灌控制系统的远程监控、管理和故障报警。论文在分析控制系统的各种干扰来源的基础上,从硬件和软件两个方面提出了相关的抗干扰措施,提高了系统运行安全性和可靠性。更多还原

【Abstract】 The importance of automatic technology in irrigation management is discussed, the present situation and existing problems of water saving irrigation controller at home and abroad are introduced in detail and the trends for further research are also discussed.According to the requirement of water supply in student apartment d istrict of,a set of automatic system of constant pressure water supply by using variable frequency and remote monitoring and controlling which is composed of PLC, transducer, pressure sensor, pumps and electro-motors, computer and device of communication is designed to that end. This set of system has the functions like automatic constant pressure operation by using variable frequency,automatic work frequency operation, and the function of long-range controlby hand and the on the spot control by hand etc. The system has solved efficiently the problem existing in the tra- itional way of water supply, which has various supplementary functions to strengthen the reliability. The system has an organic combination with computer and Promotes the systematic overall performance.Based on the lift and pipe characteristics of a water supply system the paper analyses the mechanism of energy saving that the way of water supply by using the method of variable velocity variable frequency is superior to the traditional way of constant pressure water supply controlled by valve.Setting up in advance the parameter of the PID modual built in the transducer, a system of closed circuit using the feedback of hydraulic pressure of far biography pressure table has formed. According to the change of water consumption, with PID,in the sphere of whole rate of flow, combining the constant regulation of the pump of frequency con- version with the work frequency pump grade regulation, the system of closed circuit can realize the constant pressure water supply and save energy efficiently.This paper the control strategy was put forward that two pumps were controlled in grades and freqeequency conversion by turns, and analyses the conversion condition and the various states of water supply of the two pumps way of water supply . At some time, analyses the switch process and the problem of agenerator from variable frequency operation mode to work frequenay operation mode, providing specific cut-over methods and control circuits.By researching the communication agreement between the computer and PLC,this paper has finished setting up the communication between upper and lower computer , and also has developed computer monitoring program to realize the long-range monitoring and fault reporting for water supply system through communication modular.The paper on the basis of analyses the inverters jamming source ofcontrol system, from two aspects of handware and software, advanced some anti-interference technology measures ,the reliability and continuity of the system have strengthened.更多还原