自動(dòng)加料機(jī)PLC控制系統(tǒng)（最終BETA）

摘要

針對傳統(tǒng)的繼電接觸器控制的自動(dòng)加料控制系統(tǒng)精度低、故障率高等缺點(diǎn)，本文提出了用PLC取代繼電接觸器對系統(tǒng)進(jìn)行控制的方案。本文設(shè)計(jì)的以化肥袋裝自動(dòng)加料機(jī)控制系統(tǒng)為例，采用西門子公司的S7-200系列，主機(jī)為CPU226，模擬量輸入模塊選用的是EM231。在精度控制上，采用了秤體機(jī)械結(jié)構(gòu),設(shè)置一緩沖料斗將物料送往稱斗,由稱重傳感器實(shí)現(xiàn)電子稱量?？刂破鞲鶕?jù)稱重傳感器的檢測信號(hào)順序控制緩沖料斗、稱量斗、包裝機(jī)構(gòu)的動(dòng)作,由可編程控制器通過軟件對稱重誤差進(jìn)行補(bǔ)償,提高計(jì)量精度。采用二級(jí)給料方式,粗給料流量大,而細(xì)給料流量小。前者側(cè)重于自動(dòng)加料的速度,后者保證自動(dòng)加料稱量的精度,解決了加料效率與加料稱量精度之間的矛盾。按照以上設(shè)計(jì)思路設(shè)計(jì)出了程序流程圖和功能模塊圖，并設(shè)計(jì)出梯形圖。為考慮系統(tǒng)的硬件的合理性及經(jīng)濟(jì)性，傳感器和執(zhí)行機(jī)構(gòu)分別選擇的是BK-2型S形測力/稱重傳感器和ZDLP型電子式電動(dòng)單座、套筒調(diào)節(jié)閥。
實(shí)踐證明，本控制系統(tǒng)具有精度高、成本低、抗干擾能力強(qiáng)、故障率低、操作維護(hù)簡單等特點(diǎn)，具有良好的應(yīng)用價(jià)值。
關(guān)鍵詞： 可編程控制器；自動(dòng)加料機(jī)控制系統(tǒng)；二級(jí)給料方式

ABSTRACT

According to automatic charging equipment control system of traditional relay contactor control with low accuracy and high failure rate, this paper has put forward PLC to substitute relay contactor control system. This paper takes the design of automatic charging equipment for fertilizer packaging as an example. This kind of control system adopts S7-200 product seriation made by Siemens—CPU226 host computer, EM231 for analog variable input module. In the control accuracy, it has employed the mechanical structure whose function like scales, installed a buffer bunker to transport materials, and then achieved electronic weighing by weighing transducer. The controller conducted by detection signal sequence of weighing transducer to control the motion of buffer hopper, weighing hopper and packing system, which uses software controlled by PLC to compensate weighing errors to improve measuring accuracy. Besides, the controller also adopts methods of secondary hopper feed, that is, if the controller gives more, the feeding flow rate will be lager or vise versa. The former focuses on the speed of automatic charging, while the latter tries to guarantee the precision of automatic weighing. So it has solved the problem between charging efficiency and charging weighing accuracy. In accordance with the above design thought, program flow chart, functional module and ladder diagram have been designed. With a view to the rationality and economical efficiency of hardware in the system, transducer and actuator are BK-2 in type, S force-measuring device/weighing transducer and ZDLP in type ZRSJP respectively.
It has been proved by practice that this control system has the characteristics of high accuracy, low cost, highly anti-jamming capability, and low failure rate, simply operating and maintaining and so on, together with good application value.
Key words: Programmable logic controller; Automatic charging equipment of PLC control system; Methods of secondary hopper feed

目錄
0 前言 1
1概述 2
1.1課題總體分析與設(shè)計(jì) 2
2 可編程控制器 4
2.1 可編程控制器的基本結(jié)構(gòu) 4
2.2 可編程控制器的工作原理 5
2.3 可編程控制器的性能 5
2.4 可編程控制器的應(yīng)用 6
3  S7-200系列可編程控制器 7
3.1 S7-200 系列PLC的CPU 7
3.2 S7-200 系列PLC的通信 8
3.3  PLC應(yīng)用中需要注意的問題 9
3.3.1 工作環(huán)境 9
3.3.2  控制系統(tǒng)中干擾及其來源 10
3.3.3  主要抗干擾措施 11
3.4 S7-200系列PLC模塊 13
3.4.1 數(shù)字量擴(kuò)展模塊 13
3.4.2 模擬量擴(kuò)展模塊與熱電阻、熱電偶擴(kuò)展模塊 13
3.3 PLC與其他方案的比較 14
4 自動(dòng)加料機(jī)PLC控制系統(tǒng)硬件設(shè)計(jì) 16
4.1 CPU選型 16
4.2  PLC輸入輸出點(diǎn)的地址分配表 16
4.3 PLC主機(jī)I/O接線圖 17
4.4 模擬量輸入模塊的選用 17
4.4.1  模擬量輸入模塊概述 17
4.4.2 模擬量輸入模塊的選用原則 18
4.4.3 模擬量輸入模塊選型 18
4.4.4 模擬量輸入模塊與傳感器接線圖 20
4.5 執(zhí)行機(jī)構(gòu)的選擇 20
4.5.1 電磁閥原理 20
4.5.2 電磁閥選用原則 21
4.5.3 電磁閥選型 22
4.5.4電磁閥與PLC的連接 22
4.6  測量機(jī)構(gòu)的選用原則 23
4.6.1 傳感器簡介 23
4.6.2 傳感器選擇的基本原則 23
4.6.3 傳感器的選型 24
4.6.4 傳感器的選用小結(jié) 24
4.6.5 傳感器信號(hào)放大電路 25
4.6.6 影響測量結(jié)果的因素及解決辦法 26
5 自動(dòng)加料機(jī)PLC控制系統(tǒng)軟件設(shè)計(jì) 27
5.1系統(tǒng)流程圖 27
5.2 控制程序設(shè)計(jì) 28
5.2.1 系統(tǒng)功能塊圖 28
5.2.2 控制程序設(shè)計(jì) 29
5.3 自動(dòng)加料機(jī)系統(tǒng)控制程序圖 31
5.4 提高系統(tǒng)動(dòng)態(tài)稱重精度的建議 37
6 技術(shù)經(jīng)濟(jì)分析 38
7結(jié) 論 39
致謝 40
參考文獻(xiàn) 41
附錄A  譯文 42
附錄B　外文文獻(xiàn) 54