單片機(jī)控制系統(tǒng)外文翻譯-wenkub.com
2024-08-29 13:48 本頁(yè)面
【正文】 壓力的測(cè)量和控制，或者壓力的不足—真空，在典型的過(guò)程控制中是極為重要的。壓力是一種普遍的工藝狀態(tài)，它也是這個(gè)星球上的一個(gè)生活條件：我們生活在向上延伸許多英里的大氣海洋的底部。 盡管大規(guī)模集成電路的應(yīng)用使小型和微型計(jì)算機(jī)的差別變得“模糊”，更復(fù)雜的過(guò)程控制器需要小型計(jì)算機(jī)實(shí)現(xiàn)他們的過(guò)程。可采用兩種處理，將控制器做成一種通用的微計(jì)算機(jī)，正像較強(qiáng)版本的業(yè)余計(jì)算機(jī)那樣；或者做成“包裹”式系統(tǒng)，按照像電磁繼電器那樣的較老式的技術(shù)進(jìn)行設(shè)計(jì)，來(lái)取代控制器。 微計(jì)算機(jī)的另一主要工程應(yīng)用是在過(guò)程控制中。這通常是低成本應(yīng)用情況，例如用于微波爐和自動(dòng)洗衣機(jī)的控制器。 微處理器在程序控制下處理數(shù)據(jù)，并控制流向和來(lái)自存儲(chǔ)器和輸入/輸出裝置的信息流。ROM可像RAM一樣被讀取，但與RAM不一樣的是不能用來(lái)存儲(chǔ)可變的信息。在每一種情況下，由于概念上的計(jì)算機(jī)存儲(chǔ)器更像一個(gè)公文柜，上述的“存儲(chǔ)器”一詞是非常不恰當(dāng)?shù)?；信息被存放在一系列已?shù)字標(biāo)記過(guò)的的“箱子”中，而且可以按照問(wèn)題由“箱子”的序列號(hào)進(jìn)行相關(guān)信息的參考定位。 微型計(jì)算機(jī)的三個(gè)組成部分。要在一個(gè)以微處理器為基礎(chǔ)的時(shí)鐘中找出執(zhí)行具有計(jì)數(shù)功能的一個(gè)特殊的硬件組成部分是不可能的，因?yàn)闀r(shí)間存儲(chǔ)在存儲(chǔ)器中，而在固定的時(shí)間間隔下由微處理器控制增值。這種主要將系統(tǒng)分成三個(gè)主要單元的分離方法是馮諾依曼在20世紀(jì)40年代所設(shè)想出來(lái)的，并且是針對(duì)微計(jì)算機(jī)的設(shè)想。 the controller can be implemented as a generalpurpose microputer rather like a more robust version lf a hobby puter, or as a ‘packaged’ system, signed for replacing controllers based on older technologies such as electromagnetic relays. In the former case the system would probably be programmed in conventional programming languages such as the ones to9 be introduced later, while in the other case a specialpurpose language might be used, for example one which allowed the function of the controller to be described in terms of relay interconnections, In either case programs can be stored in RAM, which allows them to be altered to suit changes in application, but this makes the overall system vulnerable to loss lf power unless batteries are used to ensure continuity of supply. Alternatively programs can be stored in ROM, in which case they virtually bee part of the electronic ‘hardware’ and are often referred to as firmware. More sophisticated process controllers require miniputers for their implementation, although the use of large scale integrated circuits ‘the distinction between mini and microputers, Products and process controllers of various kinds represent the majority of presentday microputer applications, the exact figures depending on one’s interpretation of the word ‘product’. Virtually all engineering and scientific uses of microputers can be assigned to one or other of these categories. But in the system we most study Pressure and Pressure Transmitters. Pressure arises when a force is applied over an area. Provided the force is one Newton and uniformly over the area of one square
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