智能紅外傳感器外文翻譯

1、<p><b>　　智能紅外傳感器</b></p><p>　　跟上不斷發(fā)展的工藝技術(shù)對(duì)工藝工程師來(lái)說(shuō)是一向重大挑戰(zhàn)。再加上為了保持目前迅速變化的監(jiān)測(cè)和控制方法的過(guò)程的要求，所以這項(xiàng)任務(wù)已變得相當(dāng)迫切。然而，紅外溫度傳感器制造商正在為用戶提供所需的工具來(lái)應(yīng)付這些挑戰(zhàn)：最新的計(jì)算機(jī)相關(guān)的硬件、軟件和通信設(shè)備，以及最先進(jìn)的數(shù)字電路。其中最主要的工具，不過(guò)是新一代的紅外溫度計(jì)---智能傳

2、感器。</p><p>　　今天新的智能紅外傳感器代表了兩個(gè)迅速發(fā)展的結(jié)合了紅外測(cè)溫和通常與計(jì)算機(jī)聯(lián)系在一起的高速數(shù)字技術(shù)的科學(xué)聯(lián)盟。這些文書(shū)被稱為智能傳感器，因?yàn)樗麄儼盐⑻幚砥髯鳛榫幊痰碾p向收發(fā)器。傳感器之間的串行通信的生產(chǎn)車間和計(jì)算機(jī)控制室。而且因?yàn)殡娐敷w積小，傳感器因此更小，簡(jiǎn)化了在緊張或?qū)擂蔚貐^(qū)的安裝。智能傳感器集成到新的或現(xiàn)有的過(guò)程控制系統(tǒng)，從一個(gè)新的先進(jìn)水平，在溫度監(jiān)測(cè)和控制方面為過(guò)程控制方面的工程師

3、提供了一個(gè)直接的好處。</p><p>　　1 集成智能傳感器到過(guò)程線</p><p>　　同時(shí)廣泛推行的智能紅外傳感器是新的，紅外測(cè)溫已成功地應(yīng)用于過(guò)程監(jiān)測(cè)和控制幾十年了。在過(guò)去，如果工藝工程師需要改變傳感器的設(shè)置，它們將不得不關(guān)閉或者刪除線傳感器或嘗試手動(dòng)重置到位。當(dāng)然也可能導(dǎo)致路線的延誤，在某些情況下，是十分危險(xiǎn)的。升級(jí)傳感器通常需要購(gòu)買一個(gè)新單位，校準(zhǔn)它的進(jìn)程，并且在生產(chǎn)線停滯的

4、時(shí)候安裝它。例如，某些傳感器的鍍鋅鐵絲廠用了安裝了大桶的熔融鉛、鋅、和/或鹽酸并且可以毫不費(fèi)力的從狹窄小道流出來(lái)。從安全利益考慮，生產(chǎn)線將不得不關(guān)閉，并且至少在降溫24小時(shí)之前改變和升級(jí)傳感器。</p><p>　　今天，工藝工程師可以遠(yuǎn)程配置、監(jiān)測(cè)、處理、升級(jí)和維護(hù)其紅外溫度傳感器。帶有雙向RS - 485接口或RS - 232通信功能的智能模型簡(jiǎn)化了融入過(guò)程控制系統(tǒng)的過(guò)程。一旦傳感器被安裝在生產(chǎn)線，工程師就可

5、以根據(jù)其所有參數(shù)來(lái)適應(yīng)不斷變化的條件，一切都只是從控制室中的個(gè)人電腦。舉例來(lái)說(shuō)，如果環(huán)境溫度的波動(dòng)，或程序本身經(jīng)歷類型、厚度、或溫度的改變，所有過(guò)程工程師需要做的是定制或恢復(fù)保存在計(jì)算機(jī)終端的設(shè)置。如果智能傳感器由于高溫度環(huán)境、電纜斷裂或者未能組成部分而失敗了，其故障進(jìn)行自動(dòng)修復(fù)。該傳感器激活觸發(fā)報(bào)警停機(jī)，防止損壞產(chǎn)品和機(jī)械。如果烤爐或冷卻器失敗了，音響和LO警報(bào)信號(hào)還可以指出哪里有問(wèn)題并且關(guān)閉生產(chǎn)線。</p><p

6、>　　1.1 延長(zhǎng)傳感器的使用壽命</p><p>　　為了使智能傳感器符合數(shù)千種不同類型的進(jìn)程，就必須完全自己定義。由于智能傳感器包含只讀（可擦除可編程只讀存儲(chǔ)器），用戶可以重新編程以滿足他們各自的具體程序要求使用的現(xiàn)場(chǎng)標(biāo)定、診斷、或來(lái)自傳感器制造商的實(shí)用軟件。</p><p>　　另一個(gè)擁有智能傳感器的好處是其固件，在其芯片的嵌入式軟件，可通過(guò)通訊聯(lián)系的升級(jí)來(lái)修訂，因此它們成為可

7、利用的-----不用從生產(chǎn)線移走傳感器。固件升級(jí)可以延長(zhǎng)一個(gè)傳感器的工作壽命，可以真正的使一個(gè)智能傳感器智能化。</p><p>　　Raytek公司的馬拉松系列的是一個(gè)全系列的1 - 2色比紅外溫度計(jì)，可以與多達(dá)32個(gè)智能傳感器聯(lián)網(wǎng)。現(xiàn)有模式包括綜合單位和光纖傳感器的電子盒套來(lái)確?？稍诟邷丨h(huán)境上安裝。</p><p>　　點(diǎn)擊一個(gè)傳感器窗口顯示了特定的傳感器的配置設(shè)置。 Windows圖

8、形界面直觀，易于使用。在配置屏幕，工藝工程師能夠監(jiān)測(cè)電流傳感器的設(shè)置,調(diào)整它們來(lái)滿足他們的需要，或重置傳感器回到工廠默認(rèn)值。所有顯示的信息都來(lái)自經(jīng)由RS - 485接口或RS - 232串口連接的傳感器。</p><p>　　頭兩欄為了給用戶輸入，第三個(gè)為了在第一時(shí)間內(nèi)監(jiān)測(cè)傳感器的參數(shù)，某些參數(shù)可以通過(guò)其他屏幕定制的程序和從PC到傳感器的命令更改。參數(shù)可以被用戶通過(guò)以下方面來(lái)改變輸入：</p>&l

9、t;p>　　?繼電器觸點(diǎn)可設(shè)定為NO （常開(kāi)）或數(shù)控（通常關(guān)閉）。</p><p>　　?中繼功能可設(shè)定警報(bào)或設(shè)定點(diǎn)。</p><p>　　?溫度單位可以改變由攝氏度至華氏度，反之亦然。</p><p>　　?顯示器和模擬輸出模式可以改變的智能傳感器，再加上一兩色的容量。</p><p>　　?激光（如傳感器配有激光瞄準(zhǔn)）可以開(kāi)啟或關(guān)閉

10、。</p><p>　　?毫安輸出設(shè)置和范圍，可作為自動(dòng)進(jìn)程觸發(fā)或警報(bào)。</p><p>　　?發(fā)射率（1色）或斜率（兩色）比熱值可設(shè)定。發(fā)射率和斜率值一般金屬和非金屬材料，并說(shuō)明如何確定發(fā)射和斜坡，通常包含在傳感器中。 </p><p>　　?信號(hào)處理定義的溫度參數(shù)返回，平均返回一個(gè)對(duì)象的平均氣溫在一段時(shí)間內(nèi);峰值舉行返回一個(gè)對(duì)象的最高溫度可能在一段時(shí)間內(nèi)或由外部

11、觸發(fā)。 </p><p>　　?音響報(bào)警/勞報(bào)警可設(shè)定警告不當(dāng)溫度的變化，在一些過(guò)程線，這可能是引發(fā)打破在一個(gè)產(chǎn)品或故障加熱器或冷卻器的內(nèi)容。 </p><p>　　?衰減表明報(bào)警并關(guān)閉設(shè)置雙色比智能傳感器，在這個(gè)例子中，如果鏡頭是95％遮蔽，報(bào)警警告說(shuō)溫度的結(jié)果可能是失去準(zhǔn)確性（稱為“骯臟的窗口”報(bào)警）。95％以上可以默默無(wú)聞的觸發(fā)一個(gè)自動(dòng)關(guān)機(jī)的進(jìn)程。</p><p&

12、gt;　　1.2 智能紅外傳感器的應(yīng)用</p><p>　　智能型紅外傳感器，可用于任何生產(chǎn)過(guò)程溫度是至關(guān)重要的高品質(zhì)的產(chǎn)品中。</p><p>　　紅外溫度傳感器可以看到監(jiān)控產(chǎn)品的各種熱工前后和干燥前后的溫度。智能傳感器上配置一個(gè)高速多點(diǎn)網(wǎng)絡(luò)（定義見(jiàn)下文），并從遠(yuǎn)程監(jiān)控的計(jì)算機(jī)上獨(dú)立尋址。各地的傳感器測(cè)量的溫度都可以以調(diào)查的數(shù)據(jù)單獨(dú)或季度的繪制成圖表，便于監(jiān)測(cè)和溫度數(shù)據(jù)過(guò)程的存檔。使用遠(yuǎn)

13、程處理功能，設(shè)置點(diǎn)、報(bào)警器、發(fā)射率、和信號(hào)處理，信息可以被下載到每個(gè)傳感器，其結(jié)果是更嚴(yán)格的過(guò)程控制。</p><p>　　1.3 遠(yuǎn)程在線尋址</p><p>　　在一個(gè)持續(xù)的和圖2相似的過(guò)程，智能傳感器可以連接到一個(gè)或其他顯示器。圖表記錄器和控制器分別在一個(gè)單獨(dú)網(wǎng)絡(luò)。該傳感器可安排在多點(diǎn)或點(diǎn)對(duì)點(diǎn)配置，或者只是簡(jiǎn)單的獨(dú)立。</p><p>　　在多點(diǎn)配置，多個(gè)傳感

14、器（多達(dá)32個(gè)在某些情況下）都可以聯(lián)結(jié)到網(wǎng)絡(luò)型電纜。每個(gè)傳感器都擁有自己的“地址”，允許它分別設(shè)定不同的操作參數(shù)。由于智能傳感器使用RS - 485接口或FSK信號(hào)（頻移鍵控）的通信，他們可以從控制室的電腦設(shè)置相當(dāng)大的距離---多達(dá)1200米（ 4000英尺）的RS - 485接口，或3000米（一點(diǎn)零零零萬(wàn)英尺）的FSK信號(hào)。有些程序使用RS - 232接口通信，但電纜的長(zhǎng)度限制到100英尺。</p><p>

15、　　在一個(gè)點(diǎn)對(duì)點(diǎn)的安裝，智能傳感器可以連接到圖表記錄、過(guò)程控制器、顯示器、以及控制計(jì)算機(jī)。在這種類型的安裝，數(shù)字通信可結(jié)合毫安電流回路作為一個(gè)完整的全方位的進(jìn)程通信軟件包。 </p><p>　　但是，有時(shí)專門的程序得需要專門軟件。一個(gè)壁紙制造商可能需要一系列的傳感器編程來(lái)檢查休息和眼淚沿著整個(gè)新聞界和涂層運(yùn)行，但每個(gè)地區(qū)都有不同的環(huán)境和地表溫度，如果發(fā)現(xiàn)表面的不正常現(xiàn)象，每個(gè)傳感器必須觸發(fā)警報(bào)。例如為了滿足客戶

16、商具體的要求，工程師們可以使用出版協(xié)議數(shù)據(jù)編寫(xiě)自己的程序。這些自定義程序可以遠(yuǎn)程在飛蟲(chóng)身上安裝傳感器而不用關(guān)閉生產(chǎn)線。</p><p>　　2 刻度的標(biāo)定和傳感器的升級(jí)</p><p>　　無(wú)論是使用多點(diǎn)、點(diǎn)對(duì)點(diǎn)、或單一的傳感器網(wǎng)絡(luò)，工藝工程師需要適當(dāng)?shù)能浖ぞ咴谧约旱膫€(gè)人計(jì)算機(jī)上來(lái)校準(zhǔn)、配置、監(jiān)控和升級(jí)這些傳感器。簡(jiǎn)單易于使用的數(shù)據(jù)采集、配置和實(shí)用程序通常是智能傳感器套件購(gòu)買時(shí)的一部分，

17、或自定義的軟件都可以使用。</p><p>　　與外地校準(zhǔn)軟件相比，智能傳感器是可校準(zhǔn)的。新的參數(shù)直接下載到傳感器的電路和傳感器的當(dāng)前參數(shù)被保存和存儲(chǔ)為計(jì)算機(jī)數(shù)據(jù)文件，以確保完整記錄校準(zhǔn)和/或參數(shù)的變化保留。一套校準(zhǔn)技術(shù)，可以包括單點(diǎn)偏移和兩到三點(diǎn)的可變溫度： ?單點(diǎn)抵消 如果一個(gè)單一的溫度在特定的過(guò)程中使用，傳感器的讀數(shù)需要重置，使其符合一個(gè)已知溫度，單點(diǎn)偏移校準(zhǔn)應(yīng)使用。這個(gè)偏移將適用于所有溫度在整個(gè)溫度范

18、圍內(nèi)工作。例如，如果一個(gè)已知的溫度沿一個(gè)浮動(dòng)的玻璃生產(chǎn)線是1800°F，智能傳感器或一系列的傳感器，都可以校準(zhǔn)那個(gè)溫度。</p><p>　　?兩點(diǎn) 如果傳感器的讀數(shù)必須符合兩個(gè)特定的溫度，這兩個(gè)點(diǎn)在校準(zhǔn)圖3所示應(yīng)選擇。這種技術(shù)使用校準(zhǔn)溫度來(lái)計(jì)算增益和偏移是適用于所有在整個(gè)溫度范圍內(nèi)的溫度。</p><p>　　?三點(diǎn)變溫度 如果這一進(jìn)程具有廣泛的溫度范圍，傳感器的讀數(shù)必須符

19、合三個(gè)具體溫度，最好的選擇是3點(diǎn)變溫度校準(zhǔn)。這種技術(shù)使用校準(zhǔn)溫度計(jì)算兩個(gè)收益和兩個(gè)偏移。第一增益和偏移適用于所有低于中點(diǎn)溫度并在第二盤以上所有的中點(diǎn)的溫度。三點(diǎn)校準(zhǔn)和多單雙點(diǎn)相比不太常見(jiàn)，但偶爾制造商需要執(zhí)行此技術(shù)，以滿足特定的標(biāo)準(zhǔn)。</p><p>　　現(xiàn)場(chǎng)校準(zhǔn)軟件還允許使用常規(guī)診斷方法，包括被運(yùn)行在智能傳感器上的電源電壓和中繼試驗(yàn)。結(jié)果讓工藝工程師知道傳感器的效果最佳，并在其做出一些必要的故障排除更加容易。&

20、lt;/p><p><b>　　3 結(jié)尾 </b></p><p>　　新一代的智能紅外溫度傳感器要求工藝工程師必須跟上新的生產(chǎn)技術(shù)和產(chǎn)量增加所帶來(lái)的變化。他們現(xiàn)在可以配置盡可能多的傳感器來(lái)滿足他們特殊控制過(guò)程的需要并且延長(zhǎng)這些傳感器壽命，遠(yuǎn)遠(yuǎn)超出先前的“不聰明”的設(shè)計(jì)。由于生產(chǎn)速度提高，設(shè)備停機(jī)時(shí)間必須減少。通過(guò)盡可能的監(jiān)測(cè)設(shè)備和微調(diào)溫度變量而無(wú)需關(guān)閉的進(jìn)程，工程師們可

21、以保持高效率的過(guò)程和提供高質(zhì)量的產(chǎn)品。智能紅外傳感器的數(shù)字化處理組件和通訊能力提供一定程度的到現(xiàn)在都沒(méi)有實(shí)現(xiàn)的靈活性、安全性和易用性。</p><p>　　紅外線（ IR ）輻射是電磁波譜，其中包括無(wú)線電波、微波、可見(jiàn)光和紫外線，以及伽馬射線和X射線。IR是在可見(jiàn)部分的頻譜和無(wú)線電波之間的。紅外波長(zhǎng)通常以微米表示并且光譜范圍由0.7至1000微米，只有0.7-14微米波段用于紅外測(cè)溫。   采用先

22、進(jìn)的光學(xué)系統(tǒng)和探測(cè)器，非接觸式紅外溫度計(jì)就可以專注于幾乎任何部分或0.7-14微米波段的部分。因?yàn)槊恳粋€(gè)對(duì)象（除黑體）排放量的最佳紅外能量在某一特定點(diǎn)沿線的紅外波段，每個(gè)過(guò)程可能需要獨(dú)特的傳感器模型與具體的光學(xué)和探測(cè)器類型。例如，一個(gè)傳感器，一個(gè)狹窄的集中在3.43微米的頻譜范圍適合用于測(cè)量表面溫度的聚乙烯和相關(guān)材料。一個(gè)傳感器設(shè)在5微米是用來(lái)衡量玻璃表面。 光傳感器用于金屬和金屬箔片。更廣泛的光譜范圍內(nèi)用來(lái)衡量溫度較低的表面，如紙、紙

23、板、聚、和鋁箔復(fù)合材料。 </p><p>　　一個(gè)對(duì)象通過(guò)它的溫度來(lái)體現(xiàn)排放紅外能量增加還是減少。它是發(fā)出能量，以目標(biāo)發(fā)射率來(lái)測(cè)量，那表明了一個(gè)物體的溫度。</p><p>　　發(fā)射率是一個(gè)術(shù)語(yǔ)，用于量化能源發(fā)光特性不同的材料和表面。紅外傳感器具有可調(diào)發(fā)射率設(shè)定，通常是從0.1到1.0，使準(zhǔn)確的測(cè)量的幾個(gè)表面類型的溫度。 </p><p>　　發(fā)出的能量來(lái)自于一個(gè)

24、對(duì)象，并通過(guò)其光學(xué)系統(tǒng)達(dá)到了紅外傳感器，其重點(diǎn)在能源上的一個(gè)或多個(gè)光敏探測(cè)器。然后探測(cè)器的紅外能量轉(zhuǎn)換成電信號(hào)，而這又是轉(zhuǎn)換成溫度值基于傳感器的校準(zhǔn)方程和目標(biāo)的發(fā)射率。這一溫度值可顯示在傳感器，或在一種智能傳感器轉(zhuǎn)換成數(shù)字輸出，并顯示在計(jì)算機(jī)終端。</p><p>　　Smart Infrared Sensors</p><p>　　Keeping up with continuously

25、 evolving process technologies is a major challenge for process engineers. Add to that the demands of staying current with rapidly evolving methods of monitoring and controlling those processes, and the assignment can be

26、come quite intimidating. However, infrared (IR) temperature sensor manufacturers are giving users the tools they need to meet these challenges: the latest computer-related hardware, software, and communications equipment

27、, as well as leading-edge digita</p><p>　　Today’s new smart IR sensors represent a union of two rapidly evolving sciences that combine IR temperature measurement with high-speed digital technologies usually

28、associated with the computer. These instruments are called smart sensors because they incorporate microprocessors programmed to act as transceivers for bidirectional, serial communications between sensors on the manufact

29、uring floor and computers in the control room (see Photo 1). And because the circuitry is smaller, the sensors are </p><p>　　Integrating Smart Sensors into Process Lines While the widespread implementatio

30、n of smart IR sensors is new, IR temperature measurement has been successfully used in process monitoring and control for decades (see the sidebar, “How Infrared Temperature Sensors Work,” below). In the past, if process

31、 engineers needed to change a sensor’s settings, they would have to either shut down the line to remove the sensor or try to manually reset it in place. Either course could cause delays in the line,</p><p>　

32、　Today, process engineers can remotely configure, monitor, address, upgrade, and maintain their IR temperature sensors. Smart models with bidirectional RS-485 or RS-232 communications capabilities simplify integration in

33、to process control systems. Once a sensor is installed on a process line, engineers can tailor all its parameters to fit changing conditions—all from a PC in the control room. If, for example, the ambient temperature flu

34、ctuates, or the process itself undergoes changes in type, thi</p><p>　　Extending a Sensor’s Useful Life</p><p>　　For smart sensors to be compatible with thousands of different types of processes

35、, they must be fully customizable. Because smart sensors contain EPROMs (erasable programmable read only memory), users can reprogram them to meet their specific process requirements using field calibration, diagnostics,

36、 and/or utility software from the sensor manufacturer.</p><p>　　Another benefit of owning a smart sensor is that its firmware, the software embedded in its chips, can be upgraded via the communications link

37、to revisions as they become available—without removing the sensor from the process line. Firmware upgrades extend the working life of a sensor and can actually make a smart sensor smarter.</p><p>　　The Rayte

38、k Marathon Series is a full line of 1- and 2-color ratio IR thermometers that can be networked with up to 32 smart sensors. Available models include both integrated units and fiber-optic sensors with electronic enclosure

39、s that can be mounted away from high ambient temperatures.</p><p>　　(see Photo 1). Clicking on a sensor window displays the configuration settings for that particular sensor. The Windows graphical interface

40、is intuitive and easy to use. In the configuration screen, process engineers can monitor current sensor settings, adjust them to meet their needs, or reset the sensor back to the factory defaults. All the displayed infor

41、mation comes from the sensor by way of the RS-485 or RS-232 serial connection.</p><p>　　The first two columns are for user input. The third monitors the sensor’s parameters in real time. Some parameters can

42、be changed through other screens, custom programming, and direct PC-to-sensor commands. Parameters that can be changed by user input include the following:</p><p>　　Relay contact can be set to NO (normally o

43、pen) or NC (normally closed).</p><p>　　Relay function can be set to alarm or setpoint.</p><p>　　Temperature units can be changed from degrees Celsius to degrees Fahrenheit, or vice versa.</p&

44、gt;<p>　　Display and analog output mode can be changed for smart sensors that have combined one- and two-color capabilities.</p><p>　　Laser (if the sensor is equipped with laser aiming) can be turned

45、on or off.</p><p>　　Milliamp output settings and range can be used as automatic process triggers or alarms.</p><p>　　Emissivity (for one-color) or slope (for two-color) ratio thermometers values

46、 can be set. Emissivity and slope values for common metal and nonmetal materials, and instructions on how to determine emissivity and slope, are usually included with sensors.</p><p>　　Signal processing defi

47、nes the temperature parameters returned. Average returns an object’s average temperature over a period of time; peak-hold returns an object’s peak temperature either over a period of time or by an external trigger.</p

48、><p>　　HI alarm/LO alarm can be set to warn of improper changes in temperature. On some process lines, this could be triggered by a break in a product or by malfunctioning heater or cooler elements.</p>

49、<p>　　Attenuation indicates alarm and shut down settings for two-color ratio smart sensors. In this example, if the lens is 95% obscured, an alarm warns that the temperature results might be losing accuracy (known a

50、s a “dirty window” alarm). More than 95% obscurity can trigger an automatic shutdown of the process.</p><p>　　Using Smart SensorsSmart IR sensors can be used in any manufacturing process in which temperatur

51、es are crucial to high-quality product. </p><p>　　Six IR temperature sensors can be seen monitoring product temperatures before and after the various thermal processes and before and after drying. The smart

52、sensors are configured on a high-speed multidrop network (defined below) and are individually addressable from the remote supervisory computer. Measured temperatures at all sensor locations can be polled individually or

53、sequentially; the data can be graphed for easy monitoring or archived to document process temperature data. Using remote ad</p><p>　　Remote Online AddressabilityIn a continuous process similar to that in Fi

54、gure 2, smart sensors can be connected to one another or to other displays, chart recorders, and controllers on a single network. The sensors may be arranged in multidrop or point-to-point configurations, or simply stand

55、 alone.</p><p>　　In a multidrop configuration, multiple sensors (up to 32 in some cases) can be combined on a network-type cable. Each can have its own “address,” allowing it to be configured separately with

56、 different operating parameters. Because smart sensors use RS-485 or FSK (frequency shift keyed) communications, they can be located at considerable distances from the control room computer—up to 1200 m (4000 ft.) for RS

57、-485, or 3000 m (10,000 ft.) for FSK. Some processes use RS-232 communications, but cable </p><p>　　In a point-to-point installation, smart sensors can be connected to chart recorders, process controllers, a

58、nd displays, as well as to the controlling computer. In this type of installation, digital communications can be combined with milliamp current loops for a complete all-around process communications package.</p>&

59、lt;p>　　Sometimes, however, specialized processes require specialized software. A wallpaper manufacturer might need a series of sensors programmed to check for breaks and tears along the entire press and coating run, b

60、ut each area has different ambient and surface temperatures, and each sensor must trigger an alarm if it notices irregularities in the surface. For customized processes such as this, engineers can write their own program

61、s using published protocol data. These custom programs can remotely re</p><p>　　Field Calibration and Sensor UpgradesWhether using multidrop, point-to-point, or single sensor networks, process engineers nee

62、d the proper software tools on their personal computers to calibrate, configure, monitor, and upgrade those sensors. Simple, easy-to-use data acquisition, configuration, and utility programs are usually part of the smart

63、 sensor package when purchased, or custom software can be used.</p><p>　　With field calibration software, smart sensors can be calibrated, new parameters downloaded directly to the sensor’s circuitry, and th

64、e sensor’s current parameters saved and stored as computer data files to ensure that a complete record of calibration and/or parameter changes is kept. One set of calibration techniques can include one-point offset and t

65、wo- and three-point with variable temperatures:</p><p>　　? One-point offset. If a single temperature is used in a particular process, and the sensor reading needs to be offset to make it match a known temper

66、ature, one-point offset calibration should be used. This offset will be applied to all temperatures throughout the entire temperature range. For example, if the known temperature along a float glass line is exactly 1800&

67、#176;F, the smart sensor, or series of sensors, can be calibrated to that temperature. </p><p>　　? Two-point. If sensor readings must match at two specific temperatures, the two-point calibration shown in Fi

68、gure 3 should be selected. This technique uses the calibration temperatures to calculate a gain and an offset that are applied to all temperatures throughout the entire range.</p><p>　　? Three-point with var

69、iable temperature. If the process has a wide range of temperatures, and sensor readings need to match at three specific temperatures, the best choice is three-point variable temperature calibration (see Figure 4). This t

70、echnique uses the calibration temperatures to calculate two gains and two offsets. The first gain and offset are applied to all temperatures below a midpoint temperature, and the second set to all temperatures above the

71、midpoint. Three-point calibration is l</p><p>　　Field calibration software also allows routine diagnostics, including power supply voltage and relay tests, to be run on smart sensors. The results let process

72、 engineers know if the sensors are performing at their optimum and make any necessary troubleshooting easier. </p><p>　　ConclusionThe new generation of smart IR temperature sensors allows process engineers

73、to keep up with changes brought on by newer manufacturing techniques and increases in production. They now can configure as many sensors as necessary for their specific process control needs and extend the life of those

74、sensors far beyond that of earlier, “non-smart” designs. As production rates increase, equipment downtime must decrease. By being able to monitor equipment and fine-tune temperature variables w</p><p>　　How

75、Infrared Temperature Sensors Work </p><p>　　Infrared (IR) radiation is part of the electromagnetic spectrum, which includes radio waves, microwaves, visible light, and ultraviolet light, as well as gamma ray

76、s and X-rays. The IRrange falls between the visible portion of the spectrum and radio waves. IR wavelengths are usually expressed in microns, with the IR spectrum extending from 0.7 to 1000 microns. Only the 0.7-14 micro

77、n band is used for IR temperature measurement.</p><p>　　Using advanced optic systems and detectors, noncontact IR thermometers can focus on nearly any portion or portions of the 0.7-14 micron band. Because e

78、very object (with the exception of a blackbody) emits an optimum amount of IR energy at a specific point along the IR band, each process may require unique sensor models with specific optics and detector types. For examp

79、le, a sensor with a narrow spectral range centered at 3.43 microns is optimized for measuring the surface temperature of polyethy</p><p>　　The intensity of an object's emitted IR energy increases or decr

80、eases in proportion to its temperature. It is the emitted energy, measured as the target's emissivity, that indicates an object's temperature.</p><p>　　Emissivity is a term used to quantify the energ

81、y-emitting characteristics of different materials and surfaces. IR sensors have adjustable emissivity settings, usually from 0.1 to 1.0, which allow accurate temperature measurements of several surface types. The emit

82、ted energy comes from an object and reaches the IR sensor through its optical system, which focuses the energy onto one or more photosensitive detectors. The detector then converts the IR energy into an electrical signal