【正文】 be ，起初過(guò)程儀表工業(yè)發(fā)展較慢。11：The standard output range for a pneumatic transmitter is 20 to 100 kPa .which is almost universally used .氣動(dòng)變送器的標(biāo)準(zhǔn)輸出范圍是20100KPa，這信號(hào)幾乎已在全球中使用。12: The terminals of source and load are interconnected by conductors(generally but not always wires).電源和負(fù)債端有導(dǎo)體連接（通常是導(dǎo)線，但少數(shù)情況下也有例外）。13: The transition form simple approximate models ,which are easy to work with ,to more realistic models produces two effects這種從簡(jiǎn)單、易用的近似模型到更加真實(shí)模型的轉(zhuǎn)移產(chǎn)生了兩個(gè)方面的影響。//First ,a larger number of variables must be included in the model . 首先，模型中必須包含眾多的變量。//Second ,a more realistic model is more likely to contain nonlinearities and timevarying parameters . 其次，更加真實(shí)的模型往往具有非線性和時(shí)變參數(shù)。//Previously ignored aspects of the system ,suck as interactions and feedback through the environment ,are more likely to be included .以前往往忽略的一些系統(tǒng)問(wèn)題，例如關(guān)聯(lián)問(wèn)題以及通過(guò)環(huán)境形式的反饋等，現(xiàn)在卻需要考慮。14：The use of instruments and control systems based on puters or microprocessors is forcing increased use of this type of signal .基于計(jì)算機(jī)或微處理器的儀器或控制系統(tǒng)的應(yīng)用正推動(dòng)這類信號(hào)的應(yīng)用不斷增加。15：The variables applied to the summing point (Xi , Xf and Xd) all have the same units ,so that xd=xi+xf. Combining Esq. (), () and () to eliminate Xo and Xf yields。//比較環(huán)節(jié)的變量（Xi , Xf and Xd）具有相同的單位，因而，xd=xi+xf。聯(lián)立（），（）和（）消除xo xf 得16：This simple circuit made up of a source ,a load and two wires is seldom ,if ever , met in practice .這種由一個(gè)電源一個(gè)負(fù)載和兩根導(dǎo)線組成的簡(jiǎn)單電路在實(shí)際中即使能碰到但也很少見(jiàn)。17: This situation can arise, for example, when a transconductance amplifier feeds an output current io to a load resistor RL, but the overall circuit is considered to give a voltage gain VL/Vi. 例如當(dāng)一個(gè)互導(dǎo)放大器提供輸出電流io 到一個(gè)負(fù)載電阻RL ,而全部網(wǎng)絡(luò)給出電壓增益為VL/Vi時(shí)，就可出現(xiàn)這種情況。18：This transmitter is mounted close to the point of measurement in the process .The transmitter outputair pressure for a pneumatic transmitteris piped to the recording or control instrument .變送器安裝在靠近過(guò)程中的測(cè)量點(diǎn)上。變送器輸出對(duì)氣動(dòng)變送器是空氣壓力通過(guò)管道傳給記錄或控制儀表。19：To make accurate temperature measurements with thermocouples ,the reference junction temperature must remain constant 。 要用熱電偶實(shí)現(xiàn)精確的溫度測(cè)量，參考端溫度必須保持恒定；//If it varies ,suitable pensation for these variations must be provided .如果會(huì)變化，必須提供這些變化的適當(dāng)補(bǔ)償。20：Touch is of particular importance for providing feedback necessary to grip delicate objects firmly without causing damage to them,對(duì)于需要反饋來(lái)緊緊握住精致脆弱的物體而不會(huì)損壞它們的用途，觸覺(jué)具有獨(dú)特的重要性。21：Transducers often produce very small output requiring amplification, they may generate signals in a form that need to be converted again before being handled by the rest of the system. 傳感器產(chǎn)生的信號(hào)常很小，需要放大，或者產(chǎn)生的信號(hào)和形式被系統(tǒng)的其它部分處理之前需要再次轉(zhuǎn)換。V: 1：Various control equipment ponents may be used to regulate a 。2：Vision can be bestowed on the robotic systems by using imaging sensors in various ways .For improving accuracy of performances ,it can help precisely adjust the robot hand by means of optical feedback control using visual sensors .在機(jī)器人系統(tǒng)中設(shè)置視覺(jué)可由各種形式的圖像傳感器來(lái)完成。為了改善運(yùn)行的精度，通過(guò)視覺(jué)傳感器的光學(xué)反饋控制，可精密地調(diào)整機(jī)器人的手臂。W: 1:We pare direct and continuous measurements of the accessible system states with signals representing their“desired values ” to form an error signal ,and use this signal to produce inputs to the system which will drive the error as close to zero as possible .而是將系統(tǒng)狀態(tài)的直接連接的測(cè)量值與表示其“希望值”型號(hào)相比較，由此產(chǎn)生一個(gè)誤差信號(hào)，再利用誤差信號(hào)產(chǎn)生系統(tǒng)的輸入，而該輸入又使誤差盡可能的接近于零。2：We have already stated that our main concern will be the study of systems for which linear ,timeinvariant differential equations provide a useful ：我們主要關(guān)心的是用線性、時(shí)不變微分方程作為實(shí)用的模型系統(tǒng)。3：Ｗe shall consider systems with several inputs ,some known as controls because they may be manipulated and others called external disturbances ,which are quite unpredictable .我們所討論的系統(tǒng)有幾個(gè)輸入，其中某些輸入稱為控制量，因?yàn)檫@些量可以人為的控制的，而另一些輸入稱為外部擾動(dòng)，他們是很難預(yù)知的。4: When an electronic pressure transmitter is used , the pressure is converted to electrical signal that may be the electric current or voltage .當(dāng)使用電子壓力變送器時(shí)，壓力就被轉(zhuǎn)換成電流或者電壓形式的電信號(hào)。5：When a pneumatic transmission system is employed ,the measurement signal is converted into pneumatic signal by the transmitter scaled from 0 to 100 percent of the measured value .當(dāng)使用電氣動(dòng)傳送系統(tǒng)時(shí)，測(cè)量信號(hào)就由變送器將比例為0%100%的測(cè)量值轉(zhuǎn)換成氣動(dòng)信號(hào)。6：Where i(t) the armature current and k1 a constant depending on the particular motor .其中i(t) 是電樞電流，k1是根據(jù)某一電機(jī)確定的常數(shù)。7： Whether an input or output impedance is raised or lowered by feedback depends on the type of amplifier to which feedback is applied , as will be shown in the next section. 通過(guò)反饋后輸入或輸出阻抗是升還是降取決于提供的反饋的放大器的類型，在下二節(jié)中，我們將討論這個(gè)問(wèn)題。8：With all the resistancetemperature measurements ,the use of three conductor RTD cable is remended ,The effect of ambient temperature variations on the cable is thereby ，建議使用三根導(dǎo)線的熱電阻探測(cè)器電纜。這樣就可降低環(huán)境溫度對(duì)電纜的影響。25 / 25