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毕业设计(论文)说明书
题目: PLC水塔控制系统
院(系): 机电工程学院
专业: 电气工程及其自动化
学生姓名:
学号:
指导教师单位: 机电工程学院
姓名:
职称: 高级工程师
题目类型:¨理论研究¨实验研究þ工程设计¨工程技术研究¨软件开发
摘要
水塔控制系统是我国住宅小区广泛应用的供水系统,传统的控制方式存在控制精度低及能耗大的缺点,研究设计的基于PLC控制的多泵循环变频恒压供水系统,采用可编程控制器、变频器以及压力变送器等器件,完成逻辑控制、变频调速和数据采样等功能,使系统实现自动控制,达到节能的目的,提高了供水系统的质量。本系统采用PLC进行逻辑控制,采用带变频器进行压力调节,系统存在工作可靠,使用方便,压力稳定,无冲击等优越性。通过PLC、变频器、继电器、接触器控制水泵机组运行状态,实现管网的恒压变流量供水要求。设备运行时,压力变送器不断将管网水压信号变换成电信号送入PLC的A/D模块进行A/D转换,转换后数字信号经PLC的PID指令处理后,获得最佳控制参数,通过D/A模块转换成模拟信号控制变频器,变频器和继电器控制元件自动调整水泵机组高效率地运行。供水系统的监控主要包括水泵的自动启停控制、水泵工频/变频的自动切换、供水压力的测量与调节、蓄水池水位的测量和调节、火灾和生活供水的自动切换、故障及异常状况的报警等。
关键词:可编程逻辑控制器;比例积分微分调节;变频器;压力变送器;恒压供水;变频调速。
Abstract
The water control system for water tower is a typical water supply system that is widely used in residential areas. The traditional control system can not e the disadvantages of lower control accuracy and larger power consumption. A giving water system was designed with transducer andcycling multi-pump based on the PLC controller to keep water pressure posed of the programmable controller, transducer and pressure transmitter, the water supply system could be controlled automatically via logic control, frequency conversion timing and data sampling. Thus it has advantages of power saving and good performances. Through the PLC, transducer, relay, contactor control unit running pumps, works to achieve variable flow constant pressure water supply requirement. Equipment run-time, the pressure transmitter keeps the pressure signal converting into electrical signal transported into the A/D unit of PLC for A/D converting, the converted digital signal after processing by the mand of PLC, turn into the best control parameters, the analog signal converted by D/A unit controls the speed of inverter, through the inverter and the relay control ponents automatically adjust the pumps to run efficiently. Monitoring of water supply system includes automatic start and stop control, automatic switching of the mode of the pumps, water pressure