【正文】 ，旋緊插頭螺冒，擰緊插頭上的螺釘。 ●不可用堅(jiān)硬的物體直接擠壓變送器膜片，以免損傷變送器。 ●變送器過(guò)載壓力不可超過(guò) 200% 。 ●變送器在運(yùn)輸過(guò)程中，應(yīng)裝在專用的包裝盒內(nèi)，采取適當(dāng)措施，避免雨、雪淋襲、強(qiáng)烈振動(dòng)、沖擊造成損壞。 本章小結(jié) 本次設(shè)計(jì) 主機(jī) PLC 選用日本三菱 FX2N48MR 可編程控制器 ， 它有 豐富齊備的控制運(yùn)算指令、優(yōu)越的性能 ； 變頻器 選用 西門(mén)子 MicroMaster430MicroMaster430 全新一代標(biāo)準(zhǔn)變頻器中的風(fēng)機(jī)和泵類(lèi)變轉(zhuǎn)矩負(fù)載專家。敏感元件采用擴(kuò)散或離子注入等工藝形成電阻并連接成惠斯通電橋，用微機(jī)械加工技術(shù)在電橋下形成壓力敏感膜片。我們?cè)诨菟雇姌蛏霞由现绷麟娫?，就?huì)產(chǎn)生一個(gè)直流電壓信號(hào)的輸出。 本章主要介紹了本次設(shè)計(jì)選用的幾種器件以及各器件的功能。本設(shè)計(jì)首先根據(jù)管網(wǎng)和水泵的運(yùn)行特性曲線，闡明了供水系統(tǒng)的變頻調(diào)速節(jié)能原理。 通過(guò)這次的畢業(yè)設(shè)計(jì)，我基本上掌握了一般的設(shè)計(jì)步驟：首先明確設(shè)計(jì)任務(wù)，以及工業(yè)生產(chǎn)所要求控制達(dá)到的具體的技術(shù)指標(biāo)通過(guò)討論思考及必要的簡(jiǎn)單實(shí)驗(yàn)和實(shí)際考查完成對(duì)總體工業(yè)生產(chǎn)實(shí)際系統(tǒng)的了解；進(jìn)而要對(duì)整個(gè)設(shè)計(jì)系統(tǒng)經(jīng)過(guò)深入的方案論證、計(jì)算以及聯(lián)系實(shí)際的生產(chǎn)工況、生產(chǎn)條件、企業(yè)經(jīng)濟(jì)等一系列條件，確立自己的設(shè)計(jì)方案，然后就是對(duì)自己確立的方案進(jìn)行硬件實(shí)現(xiàn)，包括所用元器件選型，以及控制部分整個(gè) PLC 系統(tǒng)的硬件選型與設(shè)計(jì)，接下來(lái)我們就進(jìn)入到軟件編程設(shè)計(jì)了，我們經(jīng)過(guò)流程圖繪制，搞清楚 各個(gè)部分實(shí)現(xiàn)的功能，進(jìn)而對(duì)整個(gè)系統(tǒng)進(jìn)行軟件編程實(shí)現(xiàn)，然后經(jīng)過(guò)調(diào)試確定編程準(zhǔn)確。 變頻恒壓供水系統(tǒng)集變頻技術(shù)、電氣技術(shù)、現(xiàn)代控制技術(shù)于一體。同時(shí)系統(tǒng)具有良好的節(jié)能性，這在能量日益緊缺的今天尤為重要，所以研究設(shè)計(jì)該系統(tǒng)，對(duì)于提高企業(yè)效率以及人民的生活水平、降低能耗等方面具有重要的現(xiàn)實(shí)意義。 整個(gè)設(shè)計(jì)過(guò)程同時(shí)也是自己鞏固所學(xué)知識(shí)的一個(gè)很好的學(xué)習(xí)機(jī)會(huì)，在此次設(shè)計(jì)中使我加深了對(duì)所學(xué)知識(shí)的鞏固，尤其是 PLC 和電力拖動(dòng)，還有增加了我的動(dòng)手能力，最重要的還有我們這種勇于走在技術(shù)創(chuàng)新前列的這種設(shè)計(jì)精神也是以后自己在學(xué)習(xí)和工作必須堅(jiān)持的。 張濤：基于 PLC 和變頻器的恒壓供水系統(tǒng)的設(shè)計(jì) 24 致 謝 在本次畢業(yè)設(shè)計(jì)過(guò)程中，我的指導(dǎo)教師陳躍東教授給予了無(wú)私的幫助與耐心的指導(dǎo)，解決了我在設(shè)計(jì)過(guò)程中的許許多多的疑問(wèn)，同時(shí)對(duì)自己設(shè)計(jì)過(guò)程中的某些知識(shí)盲點(diǎn)也耐心的給予講述，從而使得自己的畢業(yè)設(shè)計(jì)能順利完成。 同時(shí)，整個(gè)設(shè)計(jì)過(guò)程得到了電氣工程系的大力幫助。對(duì)次特別表示感謝！ 當(dāng)然，對(duì)設(shè)計(jì)進(jìn)行評(píng)閱的老師們也花費(fèi)了很大的精力， 尤其是周力老師對(duì)我的幫助，對(duì)于 我 整個(gè)設(shè)計(jì)的不足之處，熱忱的給予了指正。 張濤：基于 PLC 和變頻器的恒壓供水系統(tǒng)的設(shè)計(jì) 26 附錄 A：外文參考文獻(xiàn)及其翻譯 Using PLC realization constant pressure water supply Abstract： Take a quarters constant pressure water supply system as an example, introduced applies the PLC realization frequency conversion constant pressure water supply the method. In detail introduced the system hardware architecture, the principle of work and the software realization, and have produced the related control software flow chart and the PLC functional diagram Keyword： PLC。 Constant pressure water supply system。s health. In order to guarantee the plot the water supply is normal, we use PLC, matches by the different function sensor, according to the work management pressure, controls the water pump through the frequency changer the rotational speed, makes in the water pipe the pressure throughout to maintain at the appropriate scope. This kind of frequency conversion constant pressure water supply system direct substitution water tank, top digit water tank and traditional barometric pressure pot water supply installment. Moreover the water pump consumes the electric power and the electrical machinery rotational speed cubic bees the direct ratio relations, therefore the water pump velocity modulation movement energy conservation effect is extremely obvious, the average power consumption more usual water supply way saves 40%. The union uses the programmable controller, may realize the circulation frequency conversion, the electrical machinery soft start, has shortcircuits the protection, has flowed the protection function stably, the work is reliable, greatly lengthened the equipment service life design (1) The principle system will select water pumps parallel operations method, the pressure transmitter advocates the water pipe work hydraulic pressure transformation will be an electrical signal, after the simulation quantity load module, will input PLC, the pressure which the PLC basis will assign supposes the definite value and the actual examination value carries on the PID operation, the output control signal after the simulation quantity output module to the frequency changer, will adjust the water pump electrical machinery the power line voltage and the frequency. When pares the hour with the water volume, pumps under the frequency changer control the stable movement, when with the water volume as big as the water pump full speed movement cannot guarantee when pipe work pressure stable, PLC assigns the low pressure limit signal and at the same time the frequency changer high speed 安徽工程科技學(xué)院畢業(yè)設(shè)計(jì)（論文） 27 signal is examined by PLC, PLC automatically pumps the original work under the frequency conversion condition invests into the labor frequency movement, maintains the pressure the continuity, simultaneously starts the next relay pump after the frequency changer invests the movement, enlarges the pipe work to supply the water volume guarantee pressure to be stable. If pumped the revolution still not to be able to satisfy the pressure the request, then pumped in turn the frequency conversion active status under invests into the labor frequency movement, again invested a relay pump the frequency conversion movement. When with water volume reduction, first displays for the frequency changer has worked in the lowest the signal is effective, by now the pressure upper limit signal like still appeared, PLC first the labor frequency movement will pump stops, reduces supplies the water volume. When the above 2 signals still existed, PLC stopped the 2nd bench work frequency movement again the electrical machinery, pumped until last with the frequency changer constant pressure supplies water. All water pumps electrical machinery from stops and from starts to the start to stops all controlling by the frequency changer, realizes the belt to carry the soft start, avoided starting the big electric current feed pump electrical machinery to bring the impact, relatively lengthened the electrical machinery service life. At the same time, the system water supply uses the frequency conversion to pump the circulation way, by first pass the smooth pass pumps, the work pumps with the relay pump not firmly is decided, like this, both the guarantee water supply system has the relay pump, and the guarantee system pumps has the same running time, effectively prevented because the relay pump does not need to have the rust dead phenomenon for a long time, raised the equipment prehensive use factor, reduced the maintenance cost . (2) the system hardware system has selected siemens39