基于以太网的温度控制系统的设计

摘  要：随着以太网技术的迅猛发展，在工业控制领域扮演着越来越重要的角色。工业以太网作为一种新兴的网络技术，己在工业系统的管理层和控制层得到广泛应用，并有向下延伸应用于现场设备层的趋势。另一方面，嵌入式系统与以太网相结合应用于工业领域已成为一大趋势，其在自动化领域的应用前景被普遍看好。因此研究基于工业以太网的嵌入式数据监控技术具有极其重要的现实意义。
本文设计并实现了一个通过以太网远程控制电热炉温度的系统。该系统用嵌入式控制器BL2000接入以太网，用Dynamic C语言编程实现BL2000与以太网的通信，通过Web页远程监视电热炉的温度、修改恒温设置值和PID控制参数。硬件以嵌入式控制BL2000为核心；选用检测变送一体化热电偶温度传感器检测电热炉的温度，它能完成冷端补偿和非线性校正；选用具有过零触发功能的固态继电器（SSR）改变电热炉的输入功率，实现电热炉温度调节。软件采用Dynamic C和汇编语言混合编程，由温度标度变换、PID控制程序、通信程序和定时中断程序组成。设计和实现了一个嵌入式Web服务器，该Web服务器采用HTTP协议，能与客户端浏览器进行动态交互，实现了对嵌入式设各的状态查看和远程控制。
研究表明，通过植入TCP/IP协议的嵌入式控制器能够很好地实现与以太网的通信，通过Web服务器实现远程监控是可行的，它为远程控制提供了一种可行的方法。
关键字：工业以太网；温度控制；嵌入式控制器BL2000；Dynamic C语言；Web服务器
摘  要
 

The design of temperature control system base on Ethernet

ABSTRACT：With the rapid development of Ethernet, industrial Ethernet takes an important role in the industrial control system. Industrial Ethernet, as a rising technology for control networks, has been widely used in management layer and control layer of industrial control system. A further expansion into filed equipment layer is also suggested. On the other way, it is becoming popular that the application in industrial automation field of combining with embedded system and industrial Ethernet technologies, and have a good future for its can be predicted. So it is important to investigate and develop an intellectualized instrument supporting protocol of Industrial Ethernet.
This paper designs and achieves an electrothermal oven’s temperature long-distance control system by Ethernet. This system uses embedded controller BL2000 connect into Ethernet, uses Dynamic C’s program to carry out communication between BL2000 and Ethernet, uses Website to monitor electrothermal oven’s temperature, to set its temperature’s setting value and amend PID controller’s parameters. Embedded controller BL2000 is used hardware core. A thermocouple temperature sensor of examining and sending as a whole is used to examine electrothermal oven’s temperature, and it can finish cold junction compensation and nonlinearity correct. A solid state relay have zero-crossing triggering feature is used to change electrothermal oven’s input power so that achieve electrothermal oven’s temperature’s regulation. The software uses Dynamic C and assembly language mix program, composes of temperature’s degree scale conversion program, PID controller program, communication program and timing interruption program. An embedded Webserver was designed and achieved. It uses HTTP protocol to inter-active with browser of clients so that it can monitor and control the embedded device remotely.
The research indicates that it is feasible that the embedded controller which embedded TCP/IP protocol could communicate with Ethernet well and through Webserver carry out long-distance supervisory. It provides a feasible method for long-distance control.
Keywords： Industrial Ethernet; Temperature control; Embedded controller BL2000; Dynamic C; Webserver