基于PLC温度控制系统设计

现场总线测控系统设计摘要I摘要传统的加热炉电气控制系统普遍采用继电器控制技术,由于采用固定接线的硬件实现逻辑控制,使控制系统的体积增大,耗电多,效率不高且易出故障,不能保证正常的工业生产。随着计算机控制技术的发展,传统继电器控制技术必然被基于计算机技术而产生的PLC控制技术所取代。而PLC本身优异的性能使基于PLC控制的温度控制系统变的经济高效稳定且维护方便。这种温度控制系统对改造传统的继电器控制系统有相当的意义。在以PLC控制为核心，加热炉为基础的温度自动控制系统中，PLC将加热炉温度设定值与温度传感器的测量值之间的偏差经PID运算后得到的信号控制输出电压的大小，从而调节加热器加热，实现温度自动控制的目的。文章介绍了基于S7-200温度控制系统的PID调节器的实现。关键词：PLC温度控制PID调节器S7-200温度传感器现场总线测控系统设计目录I目录1课程设计任务书·····························································································12温度控制对象································································································22.1功能特点与技术参数·············································································22.2控制手段·····························································································23方案设计······································································································33.1现场总线概述······················································································33.2WinCC+S7-200温度控制系统的硬件组成·····················································63.3WinCC+S7-200温度控制系统的软件配置·····················································73.4WinCC+S7-200温度控制系统的网络结构·····················································93.5温度控制算法·····················································································104S7-200PLC控制程序的设计············································································164.1控制程序的组成··················································································164.2温度采集程序设计···············································································164.3数字滤波程序设计···············································································174.4PID控制程序设计················································································195WinCC组态··································································································205.1变量组态····························································································205.2画面组态····························································································205.3变量连接····························································································216程序调试·····································································································236.1PLC调试方法与结果·············································································236.2WinCC调试方法与结果··········································································237PID参数的整定····························································································247.1整定方法····························································································247.2整定结果及分析··················································································258技术小结·····································································································26参考文献········································································································27附录················································································································I现场总线测控系统设计课程设计任务书11课程设计任务书设计题目：基于WinCC和S7-200的温度测控系统学生姓名欧祖鸿课程名称现场总线测控系统设计专业班级测控普2007地点I502起止时间10.11.29～10.12.10设计内容及要求使用WinCC和S7-200PLC系统设计一套加热炉温度控制系统。内容及要求如下：1.接线图设计：S7-200和加热炉控制对象之间的接线图设计。2.程序设计(1)PLC控制程序设计包括温度采集程序，标度换算、数字滤波程序、PID控制程序、D/A输出程序设计等内容。(2)WinCC组态设计包括通信连接、变量组态、画面组态（温度控制回路相关参数的显示画面，温度趋势的显示画面，参数修改画面），变量连接等内容。3.温度PID控制参数的整定整定PID参数，分析不同PID对温度控制精度的影响。设计参数技术指标：1.温度采集精度：0.5%2.温度控制精度：1%进度要求第1天：选题、讲解任务、S7-200基本应用；第2天：温度控制回路接线图设计、S7-200编程；第3天：数据采集程序、换算程序、数字滤波程序、输出程序设计与调试；第4天：PID程序设计与调试；第5天：WinCC基本应用培训与训练；第6-7天：WinCC温度控制变量组态、画面设计、通信连接等；第8-9天：温度控制系统WinCC与PLC联调；第10天：撰写设计报告和检查设计结果参考资料1.廖常初.S7-200/400PLC应用技术（第2版）[M].机械工业出版社.20082.西门子自动化与驱动集团.深入浅出西门子WinCCV6[M].北京航空航天大学出版社,2005.9其它说明１.本表应在每次实施前一周由负责教师填写二份，院系审批后交院系办备案，一份由负责教师留用。２.若填写内容较多可另纸附后。3.一题多名学生共用的，在设计内容、参数、要求等方面应有所区别。教研室主任：指导教师：胡文金、刘显荣2010年11月26日现场总线测控系统设计温度控制对象22温度控制对象温度控制对象，在工业控制过程中，是相当重要的控制对象，因为温度直接的影响到了燃烧、化学反应、发酵、烘烤、蒸馏、浓度，结晶以及空气流动等物理的和化学的变化过程。温度控制的不好很有可能引起严重的安全事故，产品质量和产量等一系列的问题。温度控制是许多设备的重要的构成部分，它的功能是将温度控制在所需要的温度范围内，以利于进行工件的加工与处理。不论是在生活中还是在工业生产过程中，温度的变化对生活、生产的某些细节环节都会造成不同程度的影响，所以适时地对温度进行控制具有重要的意义。2.1功能特点与技术参数实践证明温度对象的特点是:时间常数大，滞后现象严重，反应在控制系统上，就是被控温度的变化滞后于调节器的输出。我们知道热量的传递是需要一定时间的，温度上升的快慢与其热容量的大小有关，通常温度的上升与下降和时间的关系是一个指数曲线关系。而产生滞后则与热量的传递过程有关，再者测温元件也有一定的惯性，这些都会产生滞后现象。本次设计选用的是TKPLC—2型温度控制器，该温度控制器同样的具有滞后大和惯性大的特点。该加热器用的是0V到5V的电压加热，2.2控制手段通过以上的分析，系统的总的滞后时间比较大，升温的滞后时间相对降温来说是比较小的。因此，在PID调节中，要使系统的品质变好，除了加入适当的积分以消除静态误差外，还应该加强比例作用使调节更加灵敏，减小调节时间，同时还应该加入适当的微分作用，使系统的超调量减小。现场总线测控系统设计方案设计33方案设计主要是通过实验的需要选择硬件。然后将选择的硬件组成控制系统，根据任务的要求选择西门子的S7-200的PLC，TKPLC-2型加热炉等硬件，硬件选择完成后，跟据所选择的硬件选择合适的软件进行程序设计，只有拥有完整的硬件和软件的系统才能所需要的功能。下面就仔细的介绍在设计中运用到的硬件和软件。3.1现场总线概述目前世界上存在着大约四十余种现场总线，如法国的FIP，英国的ERA，德国西门子公司Siemens的ProfiBus，挪威的FINT，Echelon公司的LONWorks，PhenixContact公司的InterBus，RoberBosch公司的CAN，Rosemounr公司的HART，CarloGarazzi公司的Dupline，丹麦ProcessData公司的P-net，PeterHans公司的F-Mux，以及ASI（ActraturSensorInterface）、MODBus、SDS、Arcnet，国际标准组织-基金会现场总线FF