电加热炉温度控制系统硬件设计.doc

毕业设计（论文） 题 目 电加热炉温度控制系统硬件设计 英文题目 The Hardware Development for Controlling Temperature of an Electronic Heating Furnace 学生姓名 班 级 指导教师 专 业 自动化 二零零六年六 月 摘要 本文以电加热炉的温度控制为被控对象，通过对电加热炉的温度控制对象特性的分析来确定电加热炉的温度控制硬件系统的设计和控制方案。 冶金、化工、机械各类工业控制中，电加热炉得到了广泛的应用，其温度控制具有非线性、大滞后、大惯性、时变性、升温单向性等特点。传统的以普通双向晶闸管(SCR) 控制的高温电加热炉采用移相触发电路改变晶闸管导通角的大小来调节输出功率, 达到自动控制电炉温度的目的。这种移相方式输出一种非正弦波, 实践表明这种控制方式产生相当大的中频干扰, 并通过电网传输, 给电力系统造成“公害”。采用固态继电器控温电路, 通过单片机控制固态继电器, 其波形为完整的正弦波, 是一种稳定、可靠、较先进的控制方法。为了降低成本和保证较高的控温精度, 采用ATMEL AT89C52芯片和通过控制过零触发型固态继电器的通断比，来控制输入到加热炉的功率，从而达到控制温度的目的。测量部分是采用铂銠10-铂热电偶。为了在工业现场应用中具有较强的抗干扰能力,采取了一系列抗干扰措施。以单片机为核心, 采用温度变送器和固态继电器控温电路, 实现对电炉温度的自动控制。该控制系统具有硬件成本低、控温精度较高、可靠性好、抗干扰能力强等特点。有较高的适用价值和理论价值。 关键字 电加热炉温度控制；AT89C52；PID闭环控制；铂銠10-铂热电偶；SSR Abstract This paper with the temperature control of electric heating furnace for the control object, by virtue of the object characteristic of analysis for temperature control of electric heating furnace then to certain the hardware system of design and control solutions for the heating furnace.In all walks of control realms,for example: The metallurgy,chemical engineering,machine and other industry control field, electric heating furnace got an extensive application, its temperature control has characteristics of non-linear,big lag,big inertial,time-variable and warm up unilateralism etc. Use bidirectional SCR that Traditional way to control temperature of heating furnace is a phase shift style thich make no doubt of could control temperature automatically but be proved to that could produce the fearfulness intermediate frequency interfere result in a common disaster to power system during transportatiion.On the contrary control, by using micro-chip computer assort with the slide state raley (SSR) to control temperature is a steady , reliable and advanced way for the intact sine wave which couldnt disturb the power system. In order to reduce and be sure of high precision ,we use ATMEL A