坩埚熔化电阻炉温度自动控制系统

坩埚熔化电阻炉温度自动控制系统

文档编号:ZD1232 文档字数:19702,页数:52 附原理图，外文翻译

摘要

本文设计的是坩埚熔化电阻炉温度自动控制系统。该系统利用单片机可以方便地实现对PID参数的选择与设定；实现工业过程中PID控制。它采用温度传感器热电偶将检测到的实际炉温进行A/D转换，再送入计算机中，与设定值进行比较，得出偏差。对此偏差按PID规律进行调整，得出对应的控制量来控制固态继电器、调节电炉的加热功率，从而实现对炉温的控制。利用8751单片机实现温度智能控制，能自动完成数据采集、处理、转换、并进行PID控制和键盘终端处理（各参数数值的修正）及显示。在设计中应该注意，采样周期不能太短，否则会使调节过程过于频繁，这样，不但执行机构不能反应，而且计算机的利用率也大为降低；采样周期不能太长, 否则会使干扰无法及时消除，使调节品质下降。目前，单片机在各行业控制系统中普遍被采用，其构成的实时控制系统日臻完善，系统总体性能也大大提高。
本系统对干扰信号的抑制能力较强，对温度的测量比较准确。而且通过PID控制算法实现了对系统参数的调节，使系统的响应更加灵敏、准确。

关键词单片机温度控制 PID调节

The Automatic Control System in Temperature in Melting Resistance Boiler

Abstract
What this text design is a automatic control in temperature in melting in resistance system. That system makes use of the single a machine can realizes expediently to the parameter of PID choice and set up; Realize industry process inside PID control. It adopts the temperature spreads to feel the actual the temperature of boiler A/ D that machine thermocouple will examine converts, sending into the calculator inside, proceeding with initial value the comparison, having to out the deviation. Press PID regulation to proceed the adjustment to this deviation, beg to should of the control measures control solid after electric appliances, from but regulate the heating power of the electric stove, from but realize to the control of the temperature of boiler. Make use of 8751 single a machines realizes the temperature intelligence controls, can complete automatically the data collect, handles, convert, combine the proceeding PID control to handles( the correction of each parameter number) with the keyboard terminal and manifestation, should notice in control process, adopt the kind period can't be too short, making regulate the process otherwise too multifarious, not only carry out the organization can't respond, but also the utilization of the calculator is big for lower; Adopt the kind period too long, interference can't on time dissolve, make regulate the quality descent. Single a machine is in each profession control system of widespread adoption, its component and solid hour controls the day in system perfect, make that temperature control the total function of the system to increases consumedly, the function is gradually perfect.
The system represses the ability of the interference signal stronger, is too more accurate to the diagraph of the temperature. And pass the PID control calculate way to regulate to the system parameter, the system responds to more prompt, and accurate.

Keywords single-chip computer temperature control PID adjuster

绪论……………………………………………………………………1
控制系统总体方案确定…………………………………………………2
2.1 系统总体方案确定……………………………………………………… 2
2.1.1 系统的组成………………………………………………………2
2.1.2 系统的工作过程…………………………………………………2
2.2 设计指标………………………………………………………………… 3
第三章   控制算法…………………………………………………………………4
3.1 控制算法的确定…………………………………………………………4
3.2 数学模型的建立…………………………………………………………4
3.3 PID控制算法……………………………………………………………4
3.4 PID参数的整定……………………………………………………………6
第四章   控制系统的硬件设计……………………………………………………9
4.1 微处理器的选择…………………………………………………………9
4.1.1 8751芯片介绍……………………………………………………9
4.1.2 时钟电路和复位电路……………………………………………11
4.2温度检测元件的选择与冷端补偿电路………………………………… 12
4.2.1 温度检测元件的选择……………………………………………12
4.2.2 冷端补偿电路……………………………………………………12
4.3 变送器的选择与设计……………………………………………………13
4.4 A/D转换芯片的选择与接口电路…………………………………………14
4.4.1 A/D转换芯片的选择………………………………………… 14
4.4.2 A/D转换器与单片机的接口电路………………………………15
4.5 I/O接口扩展………………………………………………………………16
4.5.1 可编程并行I/O芯片8255A介绍………………………………16
4.5.2 8255A与8751的接口电路……………………………………18
4.6 程序存储器扩展…………………………………………………………19
4.7 键盘、显示器接口电路…………………………………………………20
4.7.1 8255A与键盘接口电路…………………………………………20
4.7.2 8255A与显示器接口电路……………………………………22
4.8 过零检测电路…………………………………………………………23
4.8.1 调功原理…………………………………………………………23
4.8.2 过零检测电路……………………………………………………24
4.9 执行机构的选择……………………………………………………25
4.9.1 固态继电器的选择…………………………………………25
4.9.2   固态继电器的应用电路………………………………………26
4.10 系统电源………………………………………………………………26
第五章   控制系统的软件设计………………………………………………………28
5.1 系统采样周期的确定………………………………………………28
5.1.1 香农采样定理………………………………………………28
5.1.2 采样周期的选择………………………………………………28
5.2 数字滤波……………………………………………………………29
5.2.1 数字滤波的优点…………………………………………29
5.2.2 数字滤波的几种方法…………………………………………29
5.3 系统控制程序………………………………………………………………30
5.3.1 主程序流程图……………………………………………30
5.3.2 中断子程序流程图…………………………………………30
5.3.3 PID算法流程图………………………………………… 30
结束语……………………………………………………………………………34
参考文献……………………………………………………………………35
附录A：系统硬件电路原理图………………………………………………37
附录B：程序清单……………………………………………………………38

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