關(guān)于plc的畢業(yè)設(shè)計(jì)外文及翻譯-plc設(shè)計(jì)(完整版)
【正文】 些集成人機(jī)介面（ HMI）等功能，因此 PLC 在很多應(yīng)用中也已配置齊全從而替代單一的過程控制器。此外，在它們?nèi)烤邆溥@些功能的同時(shí)，它們?nèi)匀灰懈叩男詢r(jià)比而且編程簡單。許多納 米級(jí)和微型級(jí) PLC 都有高速運(yùn)算能力和控制器內(nèi)置的高頻脈沖輸出能力，使它們成為開環(huán)控制的可行解決方案。 編程語言 編程語言是反映 PLC 歷史的一個(gè)方面。 新技術(shù)已經(jīng)創(chuàng)造了另一種控制器 —— 可編程自動(dòng)化控制器（ PAC）。 PLC 將會(huì)繼續(xù)開發(fā)更成熟的連通性，使它可以將信息傳輸?shù)狡渌?PLC 系統(tǒng)、系統(tǒng)控制系統(tǒng)、數(shù)據(jù)采集（ SCADA）系統(tǒng)和企業(yè)資源計(jì)劃（ ERP）系統(tǒng)上。使用者不再 只是受過培訓(xùn)的編程人員（如設(shè)計(jì)工程師和系統(tǒng)集成人員），而是在更熟悉的設(shè)計(jì)上期待能用上人性化軟件的最終用戶。新 PLC 利用先進(jìn)的技術(shù)，使它們?cè)诠I(yè)界更容易地被采納。也許，最終用戶的最終愿望是獲得一個(gè)可以無縫地為多個(gè) PLC 和子系 統(tǒng)編程的軟件包。這使個(gè)人電腦通過使用接口卡接入到標(biāo)準(zhǔn) PLC 的 I/O 子系統(tǒng)成為可能，而這種接口卡主要是由 PLC 生產(chǎn)商或第三方開發(fā)商提供的。排在最前的、有重要特征的因素是： 1．聯(lián)網(wǎng)能力和易用性 以太網(wǎng)通信在通信領(lǐng)域中獨(dú)占熬頭。由于梯形圖長期的良好表現(xiàn)，因此梯形圖編程似乎會(huì)繼續(xù)成為最好的選擇。有時(shí)為了滿足系統(tǒng)需求，它不能用于更精密的控制平臺(tái)中。盡管串行通信仍然很受歡迎并且很可靠，但以太網(wǎng)快速地成為值得選擇的通信媒體，它有著不能被忽視的優(yōu)勢(shì)，例如：網(wǎng)速、設(shè)置簡單、布線方便、現(xiàn)成網(wǎng)絡(luò)組件的可用性、嵌入式通信設(shè)置 集成運(yùn)動(dòng)控制 另一個(gè)分配給 PLC 的任務(wù)是運(yùn)動(dòng)控制。這為 PLC 更好地適用于現(xiàn)存的設(shè)備提供了可能性，并且向主板上的其它控制系統(tǒng)通信成為可能。一個(gè)嵌有 CPU 和 I/O 的典型單元有大約 19 寸電視機(jī)那么大。s PLCs have to be data pilers and information gateways. They have to interface with bar code scanners and printers, as well as temperature and analog sensors. They need multiple protocol support to be able to connect with other devices in the process. And furthermore, they need all these capabilities while remaining costeffective and simple to program. Another primary development that has literally revolutionized the way PLCs are programmed, municate with each other and interface with PCs for HMI, SCADA or DCS applications, came from the puting world. Use of Ether munications on the plant floor has doubled in the past five years. While serial munications remain popular and reliable, Ether is fast being the munications media of choice with advantages that simply can39。t be ignored, such as: * Network speed. * Ease of use when it es to the setup and wiring. * Availability of offtheshelf working ponents. * Builtin munications setups. Integrated Motion Control Another responsibility the PLC has been tasked with is motion control. From simple openloop to multiaxis applications, the trend has been to integrate this feature into PLC hardware and software. There are many applications that require accurate control at a fast pace, but not exact precision at blazing speeds. These are applications where the standalone PLC works well. Many nano and micro PLCs are available with highspeed counting capabilities and highfrequency pulse outputs built into the controller, making them a viable solution for openloop control. The one caveat is that the controller does not know the position of the output device during the control sequence. On the other hand, its main advantage is cost. Even simple motion control had previously required an expensive option module, and at times was restricted to more sophisticate
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