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案例頻道State of the Art with Regard to Standardisation 標(biāo)準(zhǔn)化現(xiàn)狀
Industry standards can be viewed as both positive and negative toward technology development. On the one hand they limit creativity but on the other side they ensure that the apparatus of several manufacturers is compatible. The VDE/VDI 3845 standard describes, amongst other things, the important mechanical connection between pneumatic actuators and the apparatus which must be connected to it. The standard includes a defined mounting hole pattern of 30x80mm and of 30x130mm. Stem heights are 20, 30 and 50 mm. For stem diameter there is no fixed standard, therefore in the case of double sensors you must pay particular attention to this. 行業(yè)標(biāo)準(zhǔn)對(duì)于技術(shù)的發(fā)展而言利弊共存。一方面，它限制了創(chuàng)造性，但另一方面他們又確保了不同制造商的設(shè)備具備兼容性。VDE / VDI3845標(biāo)準(zhǔn)要求了諸多事項(xiàng)后，規(guī)定了氣動(dòng)驅(qū)動(dòng)器機(jī)與所連接設(shè)備之間的重要機(jī)械連接。該標(biāo)準(zhǔn)包括了對(duì)安裝孔的定義：30x80mm和30x130mm。安裝桿的高度為20，30和50毫米。對(duì)于安裝桿直徑，則沒(méi)有固定的標(biāo)準(zhǔn)，所以在雙傳感器的應(yīng)用中，用戶必須特別注意。
The Switchbox開(kāi)關(guān)盒
The term “switchbox” commonly describes the integration of sensors, cam and connectors in an enclosure, through which the mechanical connection is also made between the sensors and pneumatic actuator. This solution was designed so as not to expose the sensors to the immediate environment and influences, and to be able to use standard sensors (see fig 1). In these standard boxes, the following sensors are typically built in: 術(shù)語(yǔ)“開(kāi)關(guān)盒”通常描述在一個(gè)封閉盒中傳感器、凸輪和連接器的集成。傳感器和氣動(dòng)執(zhí)行器通過(guò)它實(shí)現(xiàn)機(jī)械連接。該解決方案旨在避免傳感器在周邊環(huán)境中的暴露或受到影響，同時(shí)能夠使用標(biāo)準(zhǔn)傳感器（見(jiàn)圖1）。在這些標(biāo)準(zhǔn)開(kāi)關(guān)盒中，典型內(nèi)置以下傳感器：
• Cylindrical sensors with a typical construction length of 40mm
• Slot sensors
• Rectangular sensors in V3 style (similar to the micro switch)
• Double sensors which are compact enough to be built in a box (see fig 2)
•圓柱型傳感器，典型長(zhǎng)度為40毫米
•槽形傳感器
•矩形V3風(fēng)格傳感器（類似于微動(dòng)開(kāi)關(guān)）
•雙傳感器，結(jié)構(gòu)緊湊置于一個(gè)盒中（見(jiàn)圖2）
• PCB solution 印刷電路板解決方案
The box is used as a terminal compartment to connect the valve position sensor and solenoid. Encoded connections are already on the circuit board, as well as the necessary LED’s. The circuit board fits in most standard boxes.
開(kāi)關(guān)盒被用作終端設(shè)備來(lái)連接閥位傳感器和電磁閥。編碼的連接器以及必要的LED指示燈已經(jīng)置于電路板上。電路板的尺寸適合大多數(shù)標(biāo)準(zhǔn)盒子。
The Open Solution開(kāi)放式解決方案
The term “open solution” describes the direct mounting of double sensors on automated or manual valves (see fig 3). Two inductive sensors mounted one on top of another in one housing give a precise indication of the open and closed position of a valve. 術(shù)語(yǔ)“開(kāi)放式解決方案”規(guī)定了自動(dòng)閥或手動(dòng)閥上的雙傳感器安裝（見(jiàn)圖3）。兩個(gè)電感式傳感器疊加安裝于一個(gè)外殼中，精確顯示了閥門的開(kāi)關(guān)位置。
Apart from compact size and very simple assembly, we find the following advantages: 除了體積小巧，組裝簡(jiǎn)單，我們還發(fā)現(xiàn)以下優(yōu)點(diǎn)：
• Round mounting holes (not slots) in the sensor housing avoid incorrect mounting distances or movement through impact or vibration which otherwise may require maintenance.
• The different alternatives of pneumatic actuators are covered by only two switching elements (pucks). The only choice which must be made is the mounting pattern, e.g. 30x80 or 30x130 (see fig 4 and fig 5)
• Switching targets in stainless steel are already built in to the puck (see fig. 3).
• Four LED’s indicate the output situation of the sensors, the presence of power and the output status of the solenoid valve.
• Thanks to the narrow detection area of the double sensor, there is no danger of a pinch point causing harm to the operator or allowing clogging from ice or dirt.
• The wiring of the solenoid valve can be routed through the sensor so that no separate cable needs to be run to the field.
•傳感器外殼上的圓形安裝孔（非槽形）可避免由于錯(cuò)誤的安裝距離或運(yùn)動(dòng)而導(dǎo)致的碰撞或震動(dòng)引起的維修。
•兩個(gè)開(kāi)關(guān)元件（圓盤）可以適應(yīng)多種不同的氣動(dòng)執(zhí)行器。唯一需要做出的選擇是安裝模式，例如： 30x80或30x130（見(jiàn)圖4和圖5）
•不銹鋼的目標(biāo)物已經(jīng)設(shè)計(jì)在圓盤上。（見(jiàn)圖3）。
•4個(gè)LED等表明該傳感器的輸出情況，電源有無(wú)和電磁閥輸出狀態(tài)。
•雙傳感器的檢測(cè)區(qū)域足夠狹窄，因而不會(huì)產(chǎn)生擠壓點(diǎn)導(dǎo)致操作人員受傷，或冰塊、灰塵形成的堵塞。
•電磁閥的接線，可經(jīng)過(guò)傳感器進(jìn)行布線，現(xiàn)場(chǎng)無(wú)需單獨(dú)電纜。
Inductive Sensors Versus Mechanical Switch電感式傳感器與機(jī)械開(kāi)關(guān)
In all areas of industry where the mechanical switch was previously a much-used solution for a diversity of control problems, nowadays the approach has changed. The sensor is now the solution. This is a consequence of the ability of sensors to offer significant speed and reliability advantages: 在工業(yè)的所有領(lǐng)域中，機(jī)械開(kāi)關(guān)曾經(jīng)一度是各種控制問(wèn)題的方案首選，而如今的方法已今非昔比，傳感器毋庸置疑為首選。因?yàn)閭鞲衅鞯墓ぷ魉俣群涂煽啃缘膬?yōu)勢(shì)十分明顯：
- Entirely solid state, as a result, no wear and tolerance modifications.
- Faster output switching
- Hysteresis and repeatability can be defined electronically much more successfully than in a mechanical device.
- No welding or corrosion of output contacts.
- Little or no influence of clogging or humidity.
- No contact bounce (output echo)
- LED indication on most sensors to show when the sensor has switched. This makes maintenance and commissioning simpler and quicker.
- 全固態(tài)，因此無(wú)磨損或誤差修改
- 快速輸出開(kāi)關(guān)狀態(tài)
- 磁滯和重復(fù)性可以比機(jī)械設(shè)備更多得進(jìn)行電子定義
- 無(wú)焊接或輸出端腐蝕
- 很少或根本不受堵塞或濕度的影響
- 無(wú)觸點(diǎn)抖動(dòng)（輸出回波）
- 大多數(shù)傳感器切換時(shí)有LED顯示。使得維護(hù)和調(diào)試更簡(jiǎn)單，快捷。
Typically the average life span of an inductive sensor is considerably longer than those of a mechanical switch. The fact that historically, very many mechanical switches were used for valve feedback is partly due to the difference in price and partly the fact that when using a switch polarity does not need to be considered. By use of modern techniques, Pepperl+Fuchs have succeeded in bringing sensors to the market which eliminate those remaining advantages of mechanical switches.
通常，一個(gè)電感式傳感器的平均壽命大大超過(guò)機(jī)械開(kāi)關(guān)。事實(shí)上，過(guò)去很多機(jī)械開(kāi)關(guān)都用于閥門反饋，是由于價(jià)格的低廉，同時(shí)也因?yàn)槲覀冊(cè)谑褂瞄_(kāi)關(guān)時(shí)極性問(wèn)題不需要考慮。通過(guò)現(xiàn)代技術(shù)，倍加福已經(jīng)成功地將傳感器推向市場(chǎng)，消除了機(jī)械式開(kāi)關(guān)僅有的一點(diǎn)優(yōu)勢(shì)。
Possible Sensors for Valve Position Detection用于閥位檢測(cè)的傳感器
Choosing the correct sensor can be achieved in 5 simple steps: 選擇正確的傳感器可按以下5個(gè)簡(jiǎn)單步驟實(shí)現(xiàn)：
Step 1: Switchbox or open solution? 步驟1：開(kāi)關(guān)盒或還是開(kāi)放式解決方案？
Weigh the aforesaid advantages and disadvantages against each other and make the choice. You either require the protection that the switchbox gives, or the simplicity and convenience of an open solution. Most valve suppliers offer as a matter of course the two solutions. You will find that switchboxes come in all sizes and weights, and in several qualities and classes.
權(quán)衡上述優(yōu)勢(shì)與缺點(diǎn)，做出選擇。您可能需要開(kāi)關(guān)盒的保護(hù)，或開(kāi)放式解決方案的簡(jiǎn)單便捷。大多數(shù)閥門供應(yīng)商都會(huì)提供兩種解決方案。你會(huì)發(fā)現(xiàn)開(kāi)關(guān)盒的體積和重量都各異，數(shù)量與種類也大相徑庭。
Step 2: Define electrically the final termination a sensor will have to the control system which regulates the process (AC, DC, Namur etc.). Of overriding importance is whether the system is used in an explosive area. We see the following electrical connection types. 步驟2：電氣定義傳感器的終端，傳感器所連接的控制系統(tǒng)調(diào)節(jié)著工作過(guò)程（交流，直流，Namur等）。極為重要的一點(diǎn)是該系統(tǒng)是否在爆炸地區(qū)使用。我們看以下的電氣連接類型。
• Three wire DC Sensors. These sensors have a separate wire beside the two wires for powering the sensor. The third wire is the output which is connected to the PLC input card or the control system. 直流三線傳感器。這些傳感器在兩條供電線路外還有一條單獨(dú)的線路。第三條線路連接到PLC輸入卡或控制系統(tǒng)上的輸出端。
• Two Wire DC sensors. Here the load is connected in series with the sensor. Many of these sensors are polarity tolerant which means that it does not matter how the wires are connected. For this reason, it is exactly the same as how you would connect a normal mechanical switch. In applications using these type of sensors, you must pay attention to the off state current in the circuit and the voltage drop of the sensor. 直流兩線傳感器。在這里，負(fù)載與傳感器串聯(lián)。許多傳感器都具備極性容差，即無(wú)需再關(guān)心接線的極性。因此，它與連接正常的機(jī)械開(kāi)關(guān)一樣簡(jiǎn)單。實(shí)際應(yīng)用這類傳感器，您一定要注意電路的漏電流及傳感器的電壓降。
• AC voltage with Normally Open (NO) and/or Normally Closed contacts. (NC). Here the load is in series with the sensor. 帶有常開(kāi)（NO）和/或常閉輸出的交流傳感器。在這里，負(fù)載與傳感器串聯(lián)。
• Two Wire universal Voltage. The sensor is connected in series with the load. Either AC Voltage or DC Voltage can be connected. 交直流兩線通用傳感器。該傳感器與負(fù)載串聯(lián)。無(wú)論交流電壓或直流電壓均可連接。
• Two Wire NAMUR; with an associated intrinsically safe barrier, these can be used in areas with an explosive atmosphere (area 0, 1 and 2). Lead breakage and short circuit monitoring are possible as standard. 兩線Namur傳感器，與相關(guān)本安產(chǎn)品一起，用于防爆環(huán)境（區(qū)域0，1和2）。可實(shí)現(xiàn)斷線及短路監(jiān)測(cè)。
• Two Wire Failsafe sensors. As per two wire Namur but subject to use of a safety rated barrier, a SIL 3 approved circuit is obtainable. 兩線故障安全傳感器。按兩線Namur傳感器標(biāo)準(zhǔn)，但是使用滿足安全級(jí)別的隔離柵，可以達(dá)到SIL3 安全等級(jí)。
Step 4: Connection possibilities第4步：連接的可能性
The manner of connection depends on the philosophy of the end-user. Such as, glands with cables or plug termination. For example, the chemical and pharma sector tend to choose cable connection by means of glanded entry to the box or sensor. 連接方式取決于最終用戶。例如，帶電纜的密封管或插頭。化學(xué)和制藥領(lǐng)域傾向于選擇電纜連接，通過(guò)電纜密封管進(jìn)入盒子或傳感器。
Step 5: Operation of the solenoid valve步驟5：電磁閥操作
Just like with the switchbox, one also has the option with double sensors to wire the solenoid by means of the sensor. The advantage lies in the fact that there is then only one cable that must be laid to the actuator與開(kāi)關(guān)盒一樣，使用雙傳感器也可以經(jīng)過(guò)傳感器進(jìn)行電磁閥的布線，其優(yōu)勢(shì)就在于執(zhí)行器只需要一根電纜連接。
Finally, one must verify a number of general properties of the sensor to be certain the sensor will function perfectly in the application. 最后，您必須確認(rèn)傳感器的諸多特性以確保傳感器在應(yīng)用中完美運(yùn)行。
Some examples of this are the off state current, voltage drop, environmental surroundings, maximum output current and operating voltage.
If possible one can verify by means of the specifications of the selected sensor also if quiescent current (disturbances), shock and vibration maximum values are not exceeded.類似的例子便是漏電流、電壓降，周圍環(huán)境，最大輸出電流和工作電壓。 如果可能，您可以通過(guò)選定傳感器的規(guī)格來(lái)確認(rèn)，保證在靜態(tài)電流（干擾），沖擊和振動(dòng)最大值的允許范圍內(nèi)。
Trends and Future Developments未來(lái)的發(fā)展
Because installations are very often adapted to the newest technology in order to work more efficiently and reliably, all kind of bus systems have entered the market. 由于安裝過(guò)程經(jīng)常要適應(yīng)最新的技術(shù)發(fā)展，以提高工作效率和穩(wěn)定性，各種總線系統(tǒng)開(kāi)始進(jìn)入市場(chǎng)。
Of course producers of switchboxes and actuators want to anticipate this and we see that a number of these manufacturers have developed interfaces, in consultation with sensor manufacturers, to these bus systems. A good example of this is switchboxes with AS interface incorporated because this bus system is particularly suitable for digital information. If the end user wishes to use standard sensors, appropriate field mountable modules can be found for AS_interface, Profibus PA or foundation Fieldbus (see fig6).
開(kāi)關(guān)盒和執(zhí)行器的生產(chǎn)商當(dāng)然希望加入。我們看到許多這樣的制造商已經(jīng)與傳感器制造商協(xié)商開(kāi)發(fā)出了這些總線系統(tǒng)的接口。帶AS-i的開(kāi)關(guān)盒便是一個(gè)很好的例子，因?yàn)檫@種總線系統(tǒng)特別適合數(shù)字信息。如果最終用戶希望使用標(biāo)準(zhǔn)傳感器，便需要合適的現(xiàn)場(chǎng)安裝模塊，如AS-interface，Profibus PA或基金會(huì)現(xiàn)場(chǎng)總線（參見(jiàn)圖6）。
On the other hand we see also electric actuators and positioners used with Profibus or foundation Fieldbus interface. It seems that more and more companies are realising the advantages of bus systems and particularly the combination of a field bus (for example Profibus) with AS interface is seen in installations more commonly.
另一方面，我們也看到使用帶有Profibus或基金會(huì)現(xiàn)場(chǎng)總線接口的電氣執(zhí)行器和定位系統(tǒng)。顯然越來(lái)越多的公司意識(shí)到總線系統(tǒng)的優(yōu)勢(shì)，特別是帶AS-i的現(xiàn)場(chǎng)總線組合（如Profibus）十分多見(jiàn)。
Conclusion結(jié)論
We are increasingly seeing inductive sensors replacing the mechanical switch. In some markets, 60-70% of switchboxes are fitted with inductive proximity switches which have replaced mechanical forbearers. For valve position detection standardisation is still some way off. This is due to the original starting point from which switchboxes have been devised and therefore a large mixture of mechanical assemblies and switch technologies exist.
More commonly, end-users also frequently ask for solutions which lend themselves to greater reliability to allow for long term payback from the switchbox. 我們?cè)絹?lái)越多感受到電感式傳感器取代機(jī)械開(kāi)關(guān)的趨勢(shì)。在某些市場(chǎng)，60-70%裝有電感式開(kāi)關(guān)的開(kāi)關(guān)盒已取代了機(jī)械式開(kāi)關(guān)。閥位檢測(cè)的標(biāo)準(zhǔn)化還有一段路要走。這是因?yàn)樵瓉?lái)開(kāi)關(guān)盒設(shè)計(jì)的起點(diǎn)中機(jī)械裝配和開(kāi)關(guān)技術(shù)的大量混合存在著。更常見(jiàn)的是，最終用戶也經(jīng)常要求提供更為可靠的解決方案，著眼于開(kāi)關(guān)盒的長(zhǎng)期回報(bào)。
Sensor companies have continued development and innovation and it can be seen that an enormous mixture of sensors exist which can be assembled in all kinds of switchbox. 傳感器公司的持續(xù)發(fā)展和創(chuàng)新使得大量傳感器的混合存在，以便裝配于各種開(kāi)關(guān)盒中。
In certain industries a clear tendency to the open solution is noticeable due to a price that comes close to that of the switchbox solution with mechanical contacts. Fitting valve position feedback on manual valves now also becomes a more attractive option with the size and cost of the open solution.
在某些行業(yè)領(lǐng)域中，開(kāi)放式解決方案是一個(gè)明顯的趨勢(shì)，因?yàn)樗膬r(jià)格很接近于機(jī)械接觸的開(kāi)關(guān)盒方案。現(xiàn)在由于開(kāi)放式解決方案的尺寸和成本的優(yōu)勢(shì)，在手動(dòng)閥上裝配位置反饋也變得更有吸引力。
北京市公安局海淀分局備案號(hào)：11010802023656號(hào)