基于PLC的电厂输煤控制系统

I摘要输煤系统是电厂的重要组成部分，电厂输煤系统运作的性能关系到电厂生产效率以及工人的身体健康。由于早期的输煤系统的自动化水平不高，人工作业量大，维护困难等缺点，与现代化工业需求不相适应，因此提高输煤系统自动化程度是必然选择。电厂输煤以往的控制方式落后，本文采用S7-200系列的PLC，以PLC为核心，设计电厂输煤控制系统，实现输煤系统的启停，进煤量的检测与调节，及备用系统自动切换功能。首先从输煤系统工艺流程出发，对控制系统分析，设计合理的方案。其次，在硬件部分中对各设备选型，分析需要控制的量，有称重信号，速度信号，报警信号，各设备启停，进煤量调节。以S7-200PLC作为主控制器，设计电机和变频器的控制电路，绘制电气控制原理图，通过PLC对变频器的控制达到对皮带机运行速度的控制，从而实现进煤量的调节。最后，在软件部分，设计系统流程图和编写系统的控制程序，以及对组态监控界面的设计实现对系统的监控。在这输煤系统中，进煤量控制调节由触摸屏监控，不用在工业现场人工操作，减少工作量，提高输煤效率。关键词：输煤系统；PLC；变频器；监控IIAbstractThecoalhandlingsystemisanimportantpartofpowerplant,andtheoperatingperformanceofcoalhandlingsystemwillaffecttheproductivityofapowerplantandthehealthofitsworkers.Sincetheearlycoalhandlingsystemshavethedefectssuchaslowautomationlevel,alargeamountofmanualworkandmaintenancedifficulties,whichareincompatiblewiththeneedsofmodernindustry,increasingtheautomationslevelofcoalhandlingsystemisinevitable.Thepreviouscontrolmethodsofthecoalhandlingsystemarebackward.ThisthesisusedtheS7-200seriesofPLCasthecoretodesignthecoalhandlingcontrolsystemwhichcouldrealizestartandstopofcoalhandlingsystem,detectionandregulationofcoalfeedandautomaticswitchingofbackupsystem.First,withthetechnologicalprocessofthecoalhandlingsystemasastartingpoint,itanalyzedthecontrolsystemanddesignedareasonableplan.Second,inthehardwarepart,itselectedvariousdevicesandanalyzedtheamounttobecontrolled,suchasweighingsignal,speedsignal,alarmsignal,motorstart-stopaswellascoaltestingandregulation.WithS7-200PLCasthemastercontroller,itdesignedthecontrolcircuitofmotorandtransducer,drewtheelectricalcontrolschematics,andrealizedcontroloverthebeltconveyorspeedthroughcontroloverinverterviaPLC,soastoregulatethecoalfeed.Finally,inthesoftwarepart,itdesignedthesystemflowchart,wrotethesystemcontrolprogram,anddesignedtheconfigurationmonitoringinterfacetomonitorthesystem.Inthecoalconveyingsystem,coalfeedcontrolandregulationaremonitoredviathetouchscreen,whichrequiresnomanualoperationintheindustrialfield,reducesworkload,andimprovesthecoalhandlingefficiency.Keywords：Coalhandlingsystem；PLC；Inverter；MonitorIII目录第1章绪论............................................................................................................11.1输煤系统的背景.......................................................................................11.2输煤系统的现状.......................................................................................11.3课题研究的内容及意义...........................................................................2第2章方案设计....................................................................................................42.1概述...........................................................................................................42.2系统方案分析设计...................................................................................42.2.1系统工艺流程................................................................................42.2.2系统分析设计................................................................................52.2.3进煤量控制算法............................................................................72.3系统组成总体结构...................................................................................9第3章控制系统设计..........................................................................................103.1PLC简介及选型......................................................................................103.1.1PLC的概念及发展.......................................................................103.1.2工作原理......................................................................................103.1.3基本结构......................................................................................113.1.4PLC选型.......................................................................................123.2系统设备选型.........................................................................................143.2.1给煤机..........................................................................................143.2.2皮带机..........................................................................................153.2.3滚轴筛..........................................................................................173.2.4碎煤机..........................................................................................183.2.5犁煤器..........................................................................................203.2.6皮带秤..........................................................................................213.2.7锅炉..............................................................................................223.2.8温度传感器..................................................................................233.2.9称重传感器..................................................................................243.2.10速度传感器................................................................................253.3触摸屏通讯.............................................................................................263.4变频调速.................................................................................................27IV3