【正文】 be ，起初過程儀表工業(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 .氣動變送器的標準輸出范圍是20100KPa，這信號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).電源和負債端有導體連接（通常是導線，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這種從簡單、易用的近似模型到更加真實模型的轉(zhuǎn)移產(chǎn)生了兩個方面的影響。//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，更加真實的模型往往具有非線性和時變參數(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)問題，例如關聯(lián)問題以及通過環(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 .基于計算機或微處理器的儀器或控制系統(tǒng)的應用正推動這類信號的應用不斷增加。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 .這種由一個電源一個負載和兩根導線組成的簡單電路在實際中即使能碰到但也很少見。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. 例如當一個互導放大器提供輸出電流io 到一個負載電阻RL ,而全部網(wǎng)絡給出電壓增益為VL/Vi時，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程中的測量點上。變送器輸出對氣動變送器是空氣壓力通過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 。 要用熱電偶實現(xiàn)精確的溫度測量，參考端溫度必須保持恒定；//If it varies ,suitable pensation for these variations must be provided .如果會變化，必須提供這些變化的適當補償。20：Touch is of particular importance for providing feedback necessary to grip delicate objects firmly without causing damage to them,對于需要反饋來緊緊握住精致脆弱的物體而不會損壞它們的用途，觸覺具有獨特的重要性。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)生的信號常很小，需要放大，或者產(chǎn)生的信號和形式被系統(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 .在機器人系統(tǒng)中設置視覺可由各種形式的圖像傳感器來完成。為了改善運行的精度，通過視覺傳感器的光學反饋控制，可精密地調(diào)整機器人的手臂。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)的直接連接的測量值與表示其“希望值”型號相比較，由此產(chǎn)生一個誤差信號，再利用誤差信號產(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 ：我們主要關心的是用線性、時不變微分方程作為實用的模型系統(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)有幾個輸入，其中某些輸入稱為控制量，因為這些量可以人為的控制的，而另一些輸入稱為外部擾動，他們是很難預知的。4: When an electronic pressure transmitter is used , the pressure is converted to electrical signal that may be the electric current or voltage .當使用電子壓力變送器時，壓力就被轉(zhuǎn)換成電流或者電壓形式的電信號。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 .當使用電氣動傳送系統(tǒng)時，測量信號就由變送器將比例為0%100%的測量值轉(zhuǎn)換成氣動信號。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，我們將討論這個問題。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 ，建議使用三根導線的熱電阻探測器電纜。這樣就可降低環(huán)境溫度對電纜的影響。25 / 25