摘要
温度是各种工业过程最普遍、最重要的参数之一，温度控制的精度对实验结果或工业生产都会产生重要的影响。
传统的温控系统采用温控仪表和继电器式控制柜等进行控制，其主要缺点是结构复杂，体积大，故障率高，通用性差，控制精度低．人机交互困难，自动化程度低．难以满足现代生产加工的需要。随着现代传感技术与控制方法的不断革新和发展，对实时温度控制的精度以及反应快速性的要求越来越高。本文就是基于PLC的温度控制系统设计。
本文主要介绍了PLC相关知识、温度控制系统的硬件设计、软件设计，同时对传感技术、PID算法以及调压技术进行了涉及。在硬件上主要采用西门子S7-200系列CPU224XP，K型热电偶传感器及K型热电偶变送器、柱式电压调压器以及EM235模拟量输入输出扩展模块。热电偶作为温度采集元件，采集的信号经温度变送器转换盒放大后送到EM235处理，随后送入PLC进行PID运算，运算结果控制调压器对加热过程进行调节实现自动化控制。
关键词 温度控制 PLC PID
Abstract
Temperature is one of the most common variety of industrial processes, the most important parameter, the accuracy of temperature control will have an important impact on the results or industrial production.
The temperature control system is adopted in traditional temperature control meter and relay control cabinet control, its main disadvantage is the complicated structure, big volume, high failure rate, poor universality, low control accuracy. Human-computer interaction difficulties, low degree of automation. It is difficult to meet the needs of modern production and processing. With the continuous innovation and development of modern sensor technology and control method, the higher of the real-time temperature control precision and response speed are required. This article is based on the PLC temperature control system design.
This paper mainly introduced the PLC related knowledge, the temperature control system hardware design, software design, at the same time, sensor technology, PID algorithm and the pressure regulating technology is involved. The hardware mainly adopts Siemens S7-200 series CPU224XP, the column voltage type K thermocouple sensor and K type thermocouple temperature transmitter, pressure regulator and EM235 analog input and output expansion module. Thermocouple as the temperature acquisition device, the signals collected by the temperature transmitter conversion kit amplified to EM235 processing, then sent to PLC PID operation, the control voltage regulator is adjusted to realize automatic control of heating process calculation results.
Keywords temperature control PLC PID
