【摘要】在工業(yè)過(guò)程控制中，溫度的控制要求越來(lái)越高。隨著自動(dòng)化水平的逐步提高，實(shí)現(xiàn)溫度的自動(dòng)控制已成必需。本文主要介紹了利用可編程控制（PLC）進(jìn)行溫度控制與檢測(cè)的過(guò)程。詳細(xì)介紹了利用PLC的基本單元而不是特殊功能模塊構(gòu)成的控溫系統(tǒng)。PLC控溫設(shè)計(jì)主要是通過(guò)LM35溫度傳感器，LM331電壓/頻率轉(zhuǎn)換器，將溫度信號(hào)轉(zhuǎn)換成頻率信號(hào)，送入PLC進(jìn)行比較輸出，從而實(shí)現(xiàn)對(duì)溫度的自動(dòng)控制。

【關(guān)鍵詞】PLC  LM35  LM331  控溫系統(tǒng)
【Abstract】In the industrial process control, temperature control of an increasingly high demand. With the gradual improvement of the level of automation, automatic control of temperature have become necessary. This paper describes the use of programmable logical controller (PLC) for temperature control and detection. Details on using the basic unit of the PLC and not the special function modules constitute the temperature control system. PLC design temperature mainly through the LM35 temperature sensor, LM331 voltage / frequency converter, the temperature signals into frequency signal into the PLC to compare the output in order to achieve automatic control of the temperature.

【Key words】PLC LM35 LM331 temperature control system

目錄
1 緒論 1
2 PLC控溫總體設(shè)計(jì)方案 2
2.1 控溫系統(tǒng)設(shè)計(jì)要求 2
2.2 PLC系統(tǒng)總體設(shè)計(jì)方案 2
2.3 PLC控溫設(shè)計(jì)所需器材 3
3 PLC控溫硬件設(shè)計(jì)部分 4
3.1 測(cè)溫電路 4
3.2 電壓/頻率轉(zhuǎn)換電路 4
3.2.1 芯片簡(jiǎn)介 4
3.2.2 電壓/頻率轉(zhuǎn)換電路 5
3.3 顯示電路 6
3.3.1 CD4511譯碼器 7
3.3.2  LED數(shù)碼管 7
3.4 電源電路 8
3.4.1 電源電路 8
3.4.2 橋式整流電路 8
3.4.3 穩(wěn)壓電路 10
3.5 PLC控制器 11
3.6 繼電器 12
4 PLC控溫軟件設(shè)計(jì)部分 15
4.1 PLC控溫設(shè)計(jì)流程圖 15
4.2 PLC控溫設(shè)計(jì)梯形圖 15
5 PLC控溫電路調(diào)試 17
5.1 電源電路調(diào)試 17
5.2  LM331及外圍電路的調(diào)試 17
5.3 顯示電路的調(diào)試 18
5.4 上機(jī)調(diào)試 18
5.5 注意事項(xiàng) 18
6 總結(jié) 19
7 致謝 20
8 參考文獻(xiàn) 21