測(cè)控技術(shù)與儀器專業(yè)英語(yǔ)[Unit12SimpleInstrumentModel]

1、Unit 12 Simple Instrument Model 簡(jiǎn)易的儀器模型1.What is null measurement and deflection measured? null measurement零量度 deflection measured 撓度測(cè)量 偏斜量1. 什么是零量度和偏斜量?2.What is the essential difference between analog sensors and digital sensors?2. 模擬傳感器和數(shù)字傳感器最基本的區(qū)別是什么? What important features do analog readout in

2、strument and digital readout instrument have?3. 模擬顯示儀表和數(shù)字顯示儀表有哪些重要的特征?What a role does an analog sensor or a digital sensor play?4. 模擬傳感器或數(shù)字傳感器扮演一個(gè)什么角色?In addressing measurement problems, it is often useful to have a conceptual model of the measurement process. This unit presents some of the fundame

3、ntal concepts of measurement in the context of a simple generalized in strument model. address 從事，忙于，地址，演講 in the context of在情況下；在背景下 strument： 激光外徑測(cè)量?jī)x在解決測(cè)量問(wèn)題的過(guò)程中，一個(gè)測(cè)量過(guò)程的概念模型常常是很有用的。在測(cè)量?jī)x器模型簡(jiǎn)單概括的情況下，本單元介紹一些測(cè)量的基本概念。Fig.12.1 presents a generalized model of a simple instrument. The physical process to b

4、e measured is in the left of the figure and the measurand is represented by an observable physical variable X. measurand 被測(cè)變量Fig.12.1提出了一種簡(jiǎn)易儀器的概念模型。物理過(guò)程在左邊的圖形中進(jìn)行測(cè)量，被測(cè)變量以一種可觀測(cè)的物理變量X描述。 Fig.12.1 Simple instrument model圖12.1 簡(jiǎn)易的儀器模型Note that the observable variable X need not necessarily be the measura

5、nd but simple related to the measurand in some known way. measurand 被測(cè)變量；被測(cè)性能；被測(cè)情況需注意的是，觀測(cè)變量X不需要一定是個(gè)被測(cè)變量，而是在一些已知的方法中簡(jiǎn)簡(jiǎn)與被測(cè)變量相關(guān)。For example, the mass of an object is often measured by the process of weighing, where the measurand is the mass but the physical measurement variable is the downward force t

6、he mass exerts in the Earths gravitational field. There are many possible physical measurement variables. A few are shown in Table 12.1. 表 12.1例如，物體的質(zhì)量通常是通過(guò)稱重來(lái)測(cè)量，被測(cè)變量是物體但是實(shí)際測(cè)量變量卻是地球引力場(chǎng)作用于物體的向下的引力。一些可以在表12.1中看出。 表 12.1 Table 12.1 Table 12.1The key functional element of the instrument model shown in F

7、ig.12.1 is the sensor, which has the function of converting the physical variable input into a signal variable output. 在圖.12.1中儀器模型的核心功能部件是傳感器，它的功能是將物理變量輸入轉(zhuǎn)換成信號(hào)變量輸出。Signal variable have the property that they can be manipulated in a transmission system, such as an electrical or mechanical circuit.在傳

8、輸系統(tǒng)中信號(hào)變量具有可操作的特性，如電子回路或機(jī)械電路。Because of this property, the signal variable can be transmitted to an output or recording device that can be remote from the sensor. 因?yàn)檫@個(gè)特性，信號(hào)變量可以被傳送到一個(gè)遠(yuǎn)離傳感器的輸出或記錄裝置。In electrical circuits, voltage is a common signal variable. In mechanical systems, displacement or force

9、 are commonly used as signal variables. 在電路中，電壓是一種常見(jiàn)的可變信號(hào)。在機(jī)械系統(tǒng)、位移和力通常被用做信號(hào)變量。Other examples of signal variable are shown in Table 12.1. The signal output from the sensor can be displayed, recorded, or used as an input signal to some secondary device or system. 信號(hào)變量的其他例子展現(xiàn)在表12.1。從傳感器輸出的信號(hào)能夠被顯示、記錄或者被

10、用作為一個(gè)輸入信號(hào)傳輸?shù)揭恍┐我O(shè)備或系統(tǒng)。In a basic instrument, the signal is transmitted to a display or recording device where the measurement can be read by a human observer.在一個(gè)基本儀器中，信號(hào)被傳送到一個(gè)顯示或記錄設(shè)備中以便可以被觀測(cè)者讀出。The observed output is the measurement M. There are many types of display devices, ranging from simple sca

11、les and dial gages to sophisticated computer display systems. dial gages： 各類千分尺；各類千分尺觀察結(jié)果是M。有很多類型的顯示設(shè)備，從簡(jiǎn)單的天平和各類千分尺到復(fù)雜的電腦顯示器。The signal can also be used directly by some larger system of which the instrument is a part. For example, the output signal of the sensor may be used as the input signal of a

12、 closed loop control system. a closed loop control system 閉環(huán)控制系統(tǒng)這個(gè)信號(hào)也可以通過(guò)一些較大的系統(tǒng)的儀器零件直接使用。例如，傳感器的輸出信號(hào)可作為閉環(huán)控制系統(tǒng)的輸入信號(hào)。If the signal output from the sensor is small, it is sometimes necessary to amplify the output shown in Fig.12.2.如果從傳感器輸出的信號(hào)是小的，在Fig.12.2中放大輸出量有時(shí)是必要的。 The amplified output can then be

13、transmitted to the display device or recorded, depending on the particular measurement application. 然后放大輸出可以傳送給顯示器或根據(jù)特定的測(cè)試程序記錄。 In many cases it is necessary for the instrument to provide a digital signal output so that it can interface with a computer-based data acquisition or communications system

14、. 在很多情況下，儀器提供一個(gè)數(shù)字信號(hào)輸出是很有必要的，這樣它就可以與一個(gè)以計(jì)算機(jī)為基礎(chǔ)的數(shù)據(jù)采集和通訊系統(tǒng)連接。 If the sensor does not inherently provide a digital output, then the analog output of the sensor is converted by an analog to digital converter (ADC) as shown in Fig.12.2. 如果傳感器本身不能提供一個(gè)數(shù)字輸出，那么傳感器模擬輸出將由一個(gè)模擬/數(shù)字轉(zhuǎn)換器(ADC)轉(zhuǎn)換，如圖12.2所示。 The digital s

15、ignal is typically sent to a computer processor that can display, store, or transmit the data as output to some other system, which will use the measurement. 數(shù)字信號(hào)通常發(fā)送給計(jì)算機(jī)處理器，以便可以顯示、存儲(chǔ)或傳輸數(shù)據(jù)作為其他系統(tǒng)輸出，并可以使用測(cè)量值。 Instrument model with amplifier, analog to digital converter, and computer output圖12.2 帶放大器、A

16、/D轉(zhuǎn)換器和計(jì)算機(jī)輸出的儀器模型1. Null Instrument 平衡點(diǎn)測(cè)定器，零點(diǎn)調(diào)整儀The null method is one possible mode of operation for a measuring instrument. A null instrument uses the null method for measurement. The null method 零點(diǎn)法對(duì)于測(cè)量?jī)x器零點(diǎn)法是一種合理的運(yùn)作模式。零點(diǎn)調(diào)整儀采用零點(diǎn)法作為測(cè)量方法。 In this method, the instrument exerts an influence on the meas

17、ured system so as to opposite in value, yielding a null measurement. exerts an influence on 對(duì)產(chǎn)生影響，對(duì)施加影響在該方法中，儀器對(duì)測(cè)量系統(tǒng)產(chǎn)生了影響以便與值相反，創(chuàng)造出一個(gè)無(wú)效的測(cè)量。Typically, this is accomplished by some type of feedback operation that allows the comparison of the measurand against a known standard value. measurand 被測(cè)變量；被測(cè)性

18、能；被測(cè)情況 standard value標(biāo)準(zhǔn)值通常，由某種類型的反饋操作運(yùn)行，這種類型的反饋操作允許被測(cè)變量與已知標(biāo)準(zhǔn)值進(jìn)行比較。 Key features of a null instrument include: an iterative balancing operation using some type of comparator, either a manual or automatic feedback used to achieve balance, and a null deflection at parity shown in Fig.12.3. comparator 比

19、較儀，比測(cè)儀 iterative 迭代的、重復(fù)的零點(diǎn)調(diào)整儀的主要特點(diǎn)包括：使用某種比測(cè)儀的重復(fù)平衡操作，手動(dòng)或是自動(dòng)的反饋用以實(shí)現(xiàn)平衡，和零偏斜。在圖12.3中同等顯示。圖12.3在零點(diǎn)調(diào)整儀中被測(cè)變量和已知數(shù)量物體互相平衡Fig.12.3 The measurand and the known quantities balance one another in a null instrument A null instrument offers certain intrinsic advantages over other modes of operation (e.g., see defl

20、ection instruments). deflection instrument偏轉(zhuǎn)量?jī)x器、偏擺儀器在零點(diǎn)調(diào)整儀中提供一定的內(nèi)在優(yōu)點(diǎn)優(yōu)于其他操作方式 (例如，偏擺儀器)。By balancing the unknown input against a know standard input, the null method minimizes interaction between the measuring system and the measurand. 通過(guò)平衡未知輸入和一個(gè)已知的標(biāo)準(zhǔn)的輸入，零點(diǎn)法將測(cè)量系統(tǒng)和被測(cè)變量之間的相互作用減到最小。As each input comes

21、from a separate source, the significance of any measuring influence on measurand by the measurement process in reduced. 因?yàn)槊總€(gè)輸入來(lái)自一個(gè)獨(dú)立的來(lái)源，任何測(cè)量的重要性通過(guò)測(cè)量過(guò)程降低對(duì)被測(cè)變量的影響。 In effect, the measured system sees a very high input impedance, thereby minimizing loading errors. In effect 實(shí)際上，事實(shí)上，生效 loading errors 負(fù)載

22、誤差 實(shí)際上，測(cè)量系統(tǒng)看成一個(gè)非常高的的輸入阻抗，從而減少負(fù)載誤差。 This is particularly effective when the measurand is a very small value. Hence, the null operation can achieve a high loading error. 當(dāng)被測(cè)變量是一種非常小的值時(shí)這是非常有效的。因此，零操作可達(dá)到高負(fù)載誤差。In practice, the null instrument will not achieve perfect parity due to the usable resolution o

23、f the balance and detection methods, but this is limited only by the state of the art of the circuit or scheme being employed shown in Fig.12.4.the state of the art 工藝水平 實(shí)際上，零點(diǎn)調(diào)整儀由于平衡和檢測(cè)方法的有效的分辨率不能達(dá)到完全的相等，但這僅限制于電路目前的工藝水平或使用的方案圖12.4所示。Fig.12.4 A null instrument requires input from two sources compari

24、son圖12.4 零點(diǎn)調(diào)整儀需要兩種來(lái)源比較的輸入 A disadvantage of null instruments is that an iterative balancing operation requires more time to execute than simply measuring sensor input. Thus, this method might not offer the fastest measurement possible when high-speed of measurements are required. 零點(diǎn)調(diào)整儀的缺點(diǎn)是與簡(jiǎn)單的測(cè)量傳感器輸

25、入相比迭代平衡操作需要更多時(shí)間去執(zhí)行。因此，當(dāng)要求快速測(cè)量時(shí)該方法不可能提供最快的測(cè)量。 However, the user should weigh achievable accuracy against needed speed of measurement when considering operational modes. Further, the generally not the lowest cost measuring alternative.然而，當(dāng)考慮到運(yùn)作模式時(shí)，用戶在測(cè)量精度和所需要的測(cè)量速度中進(jìn)行權(quán)衡，進(jìn)一步說(shuō)，一般不以最低成本測(cè)量所選擇。2. Deflection

26、 Instrument 偏轉(zhuǎn)量?jī)x器【第一段】The deflection method is one possible mode of operation for a measuring instrument. A deflection instrument uses the deflection method for measurement. measuring instrument 測(cè)量?jī)x表偏轉(zhuǎn)法是測(cè)量?jī)x器的一種合理的運(yùn)行模式。偏轉(zhuǎn)量?jī)x器是使用偏轉(zhuǎn)法進(jìn)行測(cè)量。A deflection instrument is influenced by the measurand so as to br

27、ing about a proportional response within the instrument. 偏轉(zhuǎn)量?jī)x器被被測(cè)變量影響以致于在儀器中導(dǎo)致相稱的響應(yīng)。This response is an output reading that is a deflection or a deviation from the initial condition of the instrument. 這種響應(yīng)是一個(gè)輸出，讀出的是從儀器的初始條件下的偏差或誤差。In a typical form, the measurand acts directly on a prime element or

28、primary circuit so as to convert its information into a detectable form. act on對(duì)起作用；按照行事 primary circuit 原電路， 初級(jí)電路 在一個(gè)典型的形式中，被測(cè)變量直接對(duì)主要因素或者初級(jí)回路起作用以便將信息轉(zhuǎn)換成一個(gè)可檢測(cè)的形式。The name is derived from a common form of instrument where is a physical deflection of a prime element that is linked to an output scale,

29、such as a pointer or other type of readout, which deflects to indicate the measured value. 這個(gè)名字源自一個(gè)常見(jiàn)的儀器，在主要元素物理偏差被連接到一個(gè)輸出，如一個(gè)指針或其他類型的讀數(shù)，轉(zhuǎn)向顯示測(cè)量值。 The magnitude of the deflection of the prime element brings about a deflection in the output scale that is designed to be proportional in magnitude to the

30、 value of the measurand. magnitude 大??；光度；重要；量級(jí) be proportional to與成比例 在輸出的測(cè)量中，主要元素的偏差大小產(chǎn)生偏差，被設(shè)計(jì)成與被測(cè)變量值的大小成比例。【第二段】Deflection instruments are the most common of measuring instruments. 偏差儀器是最常見(jiàn)的是測(cè)量?jī)x器。 The relationship between the measurand and the prime element or measuring circuit can be a direct one

31、, with no balancing mechanism or comparator circuits used. 被測(cè)變量和主要因素的關(guān)系或是測(cè)量電路可能是直接的，不需要平衡機(jī)制或是使用的比較儀電路。 The proportional response can be manipulated through signal conditioning methods between the prime element and the output scale so that the output reading is a direct indication of the measurand. signal conditioning 信號(hào)調(diào)節(jié) reading 讀數(shù)通過(guò)在主要元素和輸出比例之間的信號(hào)調(diào)節(jié)方法，這個(gè)比例的響應(yīng)能夠被人工操作，以致輸出是被測(cè)變量的直接指示。Effective designs can achiev