中英文对照翻译
智能红外传感器
跟上不断发展的工艺技术对工艺工程师来说是一向重大挑战。再加上为了保持目前迅速变化的监测和控制方法的过程的要求，所以这项任务已变得相当迫切。然而，红外温度传感器制造商正在为用户提供所需的工具来应付这些挑战：最新的计算机相关的硬件、软件和通信设备，以及最先进的数字电路。其中最主要的工具，不过是新一代的红外温度计---智能传感器。
今天新的智能红外传感器代表了两个迅速发展的结合了红外测温和通常与计算机联系在一起的高速数字技术的科学联盟。这些文书被称为智能传感器，因为他们把微处理器作为编程的双向收发器。传感器之间的串行通信的生产车间和计算机控制室。而且因为电路体积小，传感器因此更小，简化了在紧张或尴尬地区的安装。智能传感器集成到新的或现有的过程控制系统，从一个新的先进水平，在温度监测和控制方面为过程控制方面的工程师提供了一个直接的好处。
1 集成智能传感器到过程线
同时广泛推行的智能红外传感器是新的，红外测温已成功地应用于过程监测和控制几十年了。在过去，如果工艺工程师需要改变传感器的设置，它们将不得不关闭或者删除线传感器或尝试手动重置到位。当然也可能导致路线的延误，在某些情况下，是十分危险的。升级传感器通常需要购买一个新单位，校准它的进程，并且在生产线停滞的时候安装它。例如，某些传感器的镀锌铁丝厂用了安装了大桶的熔融铅、锌、和/或盐酸并且可以毫不费力的从狭窄小道流出来。从安全利益考虑，生产线将不得不关闭，并且至少在降温24小时之前改变和升级传感器。
今天，工艺工程师可以远程配置、监测、处理、升级和维护其红外温度传感器。带有双向RS - 485接口或RS - 232通信功能的智能模型简化了融入过程控制系统的过程。一旦传感器被安装在生产线，工程师就可以根据其所有参数来适应不断变化的条件，一切都只是从控制室中的个人电脑。举例来说，如果环境温度的波动，或程序本身经历类型、厚度、或温度的改变，所有过程工程师需要做的是定制或恢复保存在计算机终端的设置。如果智能传感器由于高温度环境、电缆断裂或者未能组成部分而失败了，其故障进行自动修复。该传感器激活触发报警停机，防止损坏产品和机械。如果烤炉或冷却器失败了，音响和LO 警报信号还可以指出哪里有问题并且关闭生产线。
1.1 延长传感器的使用寿命
为了使智能传感器符合数千种不同类型的进程，就必须完全自己定义。由于智能传感器包含只读（可擦除可编程只读存储器），用户可以重新编程以满足他们各自的
具体程序要求使用的现场标定、诊断、或来自传感器制造商的实用软件。
另一个拥有智能传感器的好处是其固件，在其芯片的嵌入式软件，可通过通讯联系的升级来修订，因此它们成为可利用的-----不用从生产线移走传感器。固件升级可以延长一个传感器的工作寿命，可以真正的使一个智能传感器智能化。
Raytek 公司的马拉松系列的是一个全系列的1 - 2色比红外温度计，可以与多达32个智能传感器联网。现有模式包括综合单位和光纤传感器的电子盒套来确保可在高温环境上安装。
点击一个传感器窗口显示了特定的传感器的配置设置。 Windows 图形界面直观，易于使用。在配置屏幕，工艺工程师能够监测电流传感器的设置, 调整它们来满足他们的需要，或重置传感器回到工厂默认值。所有显示的信息都来自经由RS - 485接口或RS - 232串口连接的传感器。
头两栏为了给用户输入，第三个为了在第一时间内监测传感器的参数，某些参数可以通过其他屏幕定制的程序和从PC 到传感器的命令更改。参数可以被用户通过以下方面来改变输入：
•继电器触点可设定为NO （常开）或数控（通常关闭）。
•中继功能可设定警报或设定点。
•温度单位可以改变由摄氏度至华氏度，反之亦然。
•显示器和模拟输出模式可以改变的智能传感器，再加上一两色的容量。
•激光（如传感器配有激光瞄准）可以开启或关闭。
•毫安输出设置和范围，可作为自动进程触发或警报。
•发射率（1色）或斜率（两色）比热值可设定。发射率和斜率值一般金属和非金属材料，并说明如何确定发射和斜坡，通常包含在传感器中。
•信号处理定义的温度参数返回，平均返回一个对象的平均气温在一段时间内; 峰值举行返回一个对象的最高温度可能在一段时间内或由外部触发。
•音响报警/劳报警可设定警告不当温度的变化，在一些过程线，这可能是引发打破在一个产品或故障加热器或冷却器的内容。
•衰减表明报警并关闭设置双色比智能传感器，在这个例子中，如果镜头是95％遮蔽，报警警告说温度的结果可能是失去准确性（称为“肮脏的窗口”报警）。95％以上可以默默无闻的触发一个自动关机的进程。
1.2 智能红外传感器的应用
智能型红外传感器，可用于任何生产过程温度是至关重要的高品质的产品中。 红外温度传感器可以看到监控产品的各种热工前后和干燥前后的温度。智能传感器上配置一个高速多点网络（定义见下文），并从远程监控的计算机上独立寻址。各地的传感器测量的温度都可以以调查的数据单独或季度的绘制成图表，便于监测和温度数据过程的存档。使用远程处理功能，设置点、报警器、发射率、和信号处理，信息可以被
下载到每个传感器，其结果是更严格的过程控制。
1.3 远程在线寻址
在一个持续的和图2相似的过程，智能传感器可以连接到一个或其他显示器。图表记录器和控制器分别在一个单独网络。该传感器可安排在多点或点对点配置，或者只是简单的独立。
在多点配置，多个传感器（多达32个在某些情况下）都可以联结到网络型电缆。每个传感器都拥有自己的“地址”，允许它分别设定不同的操作参数。由于智能传感器使用RS - 485接口或FSK 信号（频移键控）的通信，他们可以从控制室的电脑设置相当大的距离---多达1200米（ 4000英尺）的RS - 485接口，或3000米（一点零零零万英尺）的FSK 信号。有些程序使用RS - 232接口通信，但电缆的长度限制到100英尺。
在一个点对点的安装，智能传感器可以连接到图表记录、过程控制器、显示器、以及控制计算机。在这种类型的安装，数字通信可结合毫安电流回路作为一个完整的全方位的进程通信软件包。
但是，有时专门的程序得需要专门软件。一个壁纸制造商可能需要一系列的传感器编程来检查休息和眼泪沿着整个新闻界和涂层运行，但每个地区都有不同的环境和地表温度，如果发现表面的不正常现象，每个传感器必须触发警报。例如为了满足客户商具体的要求，工程师们可以使用出版协议数据编写自己的程序。这些自定义程序可以远程在飞虫身上安装传感器而不用关闭生产线。
2 刻度的标定和传感器的升级
无论是使用多点、点对点、或单一的传感器网络，工艺工程师需要适当的软件工具在自己的个人计算机上来校准、配置、监控和升级这些传感器。简单易于使用的数据采集、配置和实用程序通常是智能传感器套件购买时的一部分，或自定义的软件都可以使用。
与外地校准软件相比，智能传感器是可校准的。新的参数直接下载到传感器的电路和传感器的当前参数被保存和存储为计算机数据文件，以确保完整记录校准和/或参数的变化保留。一套校准技术，可以包括单点偏移和两到三点的可变温度：
•单点抵消 如果一个单一的温度在特定的过程中使用，传感器的读数需要重置，使其符合一个已知温度，单点偏移校准应使用。这个偏移将适用于所有温度在整个温度范围内工作。例如，如果一个已知的温度沿一个浮动的玻璃生产线是1800°F ，智能传感器或一系列的传感器，都可以校准那个温度。
•两点 如果传感器的读数必须符合两个特定的温度，这两个点在校准图3所示应选择。这种技术使用校准温度来计算增益和偏移是适用于所有在整个温度范围内的温度。
•三点变温度 如果这一进程具有广泛的温度范围，传感器的读数必须符合三个具
体温度，最好的选择是3点变温度校准。这种技术使用校准温度计算两个收益和两个偏移。第一增益和偏移适用于所有低于中点温度并在第二盘以上所有的中点的温度。三点校准和多单双点相比不太常见，但偶尔制造商需要执行此技术，以满足特定的标准。
现场校准软件还允许使用常规诊断方法，包括被运行在智能传感器上的电源电压和中继试验。结果让工艺工程师知道传感器的效果最佳，并在其做出一些必要的故障排除更加容易。
3 结尾
新一代的智能红外温度传感器要求工艺工程师必须跟上新的生产技术和产量增加所带来的变化。他们现在可以配置尽可能多的传感器来满足他们特殊控制过程的需要并且延长这些传感器寿命，远远超出先前的“不聪明”的设计。由于生产速度提高，设备停机时间必须减少。通过尽可能的监测设备和微调温度变量而无需关闭的进程，工程师们可以保持高效率的过程和提供高质量的产品。智能红外传感器的数字化处理组件和通讯能力提供一定程度的到现在都没有实现的灵活性、安全性和易用性。
红外线（ IR ）辐射是电磁波谱，其中包括无线电波、微波、可见光和紫外线，以及伽马射线和X 射线。IR 是在可见部分的频谱和无线电波之间的。红外波长通常以微米表示并且光谱范围由0.7至1000微米，只有0.7-14微米波段用于红外测温。
采用先进的光学系统和探测器，非接触式红外温度计就可以专注于几乎任何部分或0.7-14微米波段的部分。因为每一个对象（除黑体）排放量的最佳红外能量在某一特定点沿线的红外波段，每个过程可能需要独特的传感器模型与具体的光学和探测器类型。例如，一个传感器，一个狭窄的集中在3.43微米的频谱范围适合用于测量表面温度的聚乙烯和相关材料。一个传感器设在5微米是用来衡量玻璃表面。 光传感器用于金属和金属箔片。更广泛的光谱范围内用来衡量温度较低的表面，如纸、纸板、聚、和铝箔复合材料。
一个对象通过它的温度来体现排放红外能量增加还是减少。它是发出能量，以目标发射率来测量，那表明了一个物体的温度。
发射率是一个术语，用于量化能源发光特性不同的材料和表面。红外传感器具有可调发射率设定，通常是从0.1到1.0，使准确的测量的几个表面类型的温度。
发出的能量来自于一个对象，并通过其光学系统达到了红外传感器，其重点在能源上的一个或多个光敏探测器。然后探测器的红外能量转换成电信号，而这又是转换成温度值基于传感器的校准方程和目标的发射率。这一温度值可显示在传感器，或在一种智能传感器转换成数字输出，并显示在计算机终端。
Smart Infrared Sensors
K eeping up with continuously 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 become 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, as well as leading-edge digital circuitry. Chief among these tools, though, is the next generation of IR thermometers—the smart sensor.
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 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 manufacturing floor and computers in the control room (see Photo 1). And because the circuitry is smaller, the sensors are smaller, simplifying installation in tight or awkward areas. Integrating smart sensors into new or existing process control systems offers an immediate advantage to process control engineers in terms of providing a new level of sophistication in temperature monitoring and control.
Integrating Smart Sensors into Process Lines
While the widespread implementation 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 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, and, in some cases, be very dangerous. Upgrading a sensor usually required buying a new unit, calibrating it to the process, and installing it while the process line lay inactive. For example, some of the sensors in a wire galvanizing plant used to be mounted over vats of molten lead, zinc, and/or muriatic acid and accessible only by reaching out over the vats from a catwalk. In the interests of safety, the process line would have to be shut down for at least 24 hours to cool before changing and upgrading a sensor.
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 into 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 fluctuates, or the process itself undergoes changes in type, thickness, or temperature, all a process engineer needs to do is customize or restore saved settings at a computer terminal. If a smart sensor fails due to high ambient temperature conditions, a cut cable, or failed
components, its fail-safe conditions engage automatically. The sensor activates an alarm to trigger a shutdown, preventing damage to product and machinery. If ovens or coolers fail, HI and LO alarms can also signal that there is a problem and/or shut down the line.
Extending a Sensor’s Useful Life
For smart sensors to be compatible with thousands of different types of processes, 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, and/or utility software from the sensor manufacturer.
Another benefit of owning a smart sensor is that its firmware, the software embedded in its chips, can be upgraded via the communications link 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.
The Raytek 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 enclosures that can be mounted away from high ambient temperatures.
(see Photo 1). Clicking on a sensor window displays the configuration settings for that particular sensor. The Windows graphical interface 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 information comes from the sensor by way of the RS-485 or RS-232 serial connection.
The first two columns are for user input. The third monitors the sensor’s parameters in real time. Some parameters can be changed through other screens, custom programming, and direct PC-to-sensor commands. Parameters that can be changed by user input include the following:
∙ Relay contact can be set to NO (normally open) or NC (normally closed).
∙ Relay function can be set to alarm or setpoint.
∙ Temperature units can be changed from degrees Celsius to degrees Fahrenheit, or vice versa.
∙ Display and analog output mode can be changed for smart sensors that have combined one- and two-color capabilities.
∙ Laser (if the sensor is equipped with laser aiming) can be turned on or off.
∙ Milliamp output settings and range can be used as automatic process triggers or alarms.
∙ Emissivity (for one-color) or slope (for two-color) ratio thermometers values 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.
∙ Signal processing defines 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.
∙ 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.
∙ 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 as a “dirty window” alarm). More than 95% obscurity can trigger an automatic shutdown of the process.
Using Smart Sensors
Smart IR sensors can be used in any manufacturing process in which temperatures are crucial to high-quality product.
Six IR temperature sensors can be seen monitoring product temperatures before and after the various thermal processes and before and after drying. The smart 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 sequentially; the data can be graphed for easy monitoring or archived to document process temperature data. Using remote addressing features, set points, alarms, emissivity, and signal processing, information can be downloaded to each sensor. The result is tighter process control.
Remote Online Addressability
In a continuous process similar to that in Figure 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 alone.
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 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-485, or 3000 m (10,000 ft.) for FSK. Some processes use RS-232 communications, but cable length is limited to
In a point-to-point installation, smart sensors can be connected to chart recorders, process controllers, and 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.
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, but 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 programs using published protocol data. These custom programs can remotely reconfigure sensors on the fly —without shutting down the process line.
Field Calibration and Sensor Upgrades
Whether using multidrop, point-to-point, or single sensor networks, process engineers need 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 sensor package when purchased, or custom software can be used.
With field calibration software, smart sensors can be calibrated, new parameters downloaded directly to the sensor’s circuitry, and the 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 two- and three-point with variable temperatures:
• 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 temperature, 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°F, the smart sensor, or series of sensors, can be calibrated to that temperature.
• Two-point. If sensor readings must match at two specific temperatures, the two-point calibration shown in Figure 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.
• Three-point with variable 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 technique 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 midpoint. Three-point calibration is less common than one- and two-point, but occasionally manufacturers need to perform this technique to meet specific standards.
Field calibration software also allows routine diagnostics, including power supply voltage and relay tests, to be run on smart sensors. The results let process engineers know if the sensors are performing at their optimum and make any necessary troubleshooting easier.
Conclusion
The new generation of smart IR temperature sensors allows process engineers 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 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 without shutting down a process, engineers can keep the process efficient and the product quality high. A smart IR sensor’s digital processing components and communications capabilities provide a level of flexibility, safety, and ease of use not achieved until now.
How Infrared Temperature Sensors Work
Infrared (IR) radiation is part of the electromagnetic spectrum, which includes radio waves, microwaves, visible light, and ultraviolet light, as well as gamma rays 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 micron band is used for IR temperature measurement.
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 every 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 example, a sensor with a narrow spectral range centered at 3.43 microns is optimized for measuring the surface temperature of polyethylene and related materials. A sensor set up for 5 microns is used to measure glass surfaces. A 1 micron sensor is used for metals and foils. The broader spectral ranges are used to measure lower temperature surfaces, such as paper, board, poly, and foil composites.
The intensity of an object's emitted IR energy increases or decreases in proportion to its temperature. It is the emitted energy, measured as the target's emissivity, that indicates an object's temperature.
Emissivity is a term used to quantify the energy-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 emitted 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, which is in turn converted into a temperature value based on the sensor's calibration equation and the target's emissivity. This temperature value can be displayed on the sensor, or, in the case of the smart sensor, converted to a digital output and displayed on a computer terminal。
中英文对照翻译
智能红外传感器
跟上不断发展的工艺技术对工艺工程师来说是一向重大挑战。再加上为了保持目前迅速变化的监测和控制方法的过程的要求，所以这项任务已变得相当迫切。然而，红外温度传感器制造商正在为用户提供所需的工具来应付这些挑战：最新的计算机相关的硬件、软件和通信设备，以及最先进的数字电路。其中最主要的工具，不过是新一代的红外温度计---智能传感器。
今天新的智能红外传感器代表了两个迅速发展的结合了红外测温和通常与计算机联系在一起的高速数字技术的科学联盟。这些文书被称为智能传感器，因为他们把微处理器作为编程的双向收发器。传感器之间的串行通信的生产车间和计算机控制室。而且因为电路体积小，传感器因此更小，简化了在紧张或尴尬地区的安装。智能传感器集成到新的或现有的过程控制系统，从一个新的先进水平，在温度监测和控制方面为过程控制方面的工程师提供了一个直接的好处。
1 集成智能传感器到过程线
同时广泛推行的智能红外传感器是新的，红外测温已成功地应用于过程监测和控制几十年了。在过去，如果工艺工程师需要改变传感器的设置，它们将不得不关闭或者删除线传感器或尝试手动重置到位。当然也可能导致路线的延误，在某些情况下，是十分危险的。升级传感器通常需要购买一个新单位，校准它的进程，并且在生产线停滞的时候安装它。例如，某些传感器的镀锌铁丝厂用了安装了大桶的熔融铅、锌、和/或盐酸并且可以毫不费力的从狭窄小道流出来。从安全利益考虑，生产线将不得不关闭，并且至少在降温24小时之前改变和升级传感器。
今天，工艺工程师可以远程配置、监测、处理、升级和维护其红外温度传感器。带有双向RS - 485接口或RS - 232通信功能的智能模型简化了融入过程控制系统的过程。一旦传感器被安装在生产线，工程师就可以根据其所有参数来适应不断变化的条件，一切都只是从控制室中的个人电脑。举例来说，如果环境温度的波动，或程序本身经历类型、厚度、或温度的改变，所有过程工程师需要做的是定制或恢复保存在计算机终端的设置。如果智能传感器由于高温度环境、电缆断裂或者未能组成部分而失败了，其故障进行自动修复。该传感器激活触发报警停机，防止损坏产品和机械。如果烤炉或冷却器失败了，音响和LO 警报信号还可以指出哪里有问题并且关闭生产线。
1.1 延长传感器的使用寿命
为了使智能传感器符合数千种不同类型的进程，就必须完全自己定义。由于智能传感器包含只读（可擦除可编程只读存储器），用户可以重新编程以满足他们各自的
具体程序要求使用的现场标定、诊断、或来自传感器制造商的实用软件。
另一个拥有智能传感器的好处是其固件，在其芯片的嵌入式软件，可通过通讯联系的升级来修订，因此它们成为可利用的-----不用从生产线移走传感器。固件升级可以延长一个传感器的工作寿命，可以真正的使一个智能传感器智能化。
Raytek 公司的马拉松系列的是一个全系列的1 - 2色比红外温度计，可以与多达32个智能传感器联网。现有模式包括综合单位和光纤传感器的电子盒套来确保可在高温环境上安装。
点击一个传感器窗口显示了特定的传感器的配置设置。 Windows 图形界面直观，易于使用。在配置屏幕，工艺工程师能够监测电流传感器的设置, 调整它们来满足他们的需要，或重置传感器回到工厂默认值。所有显示的信息都来自经由RS - 485接口或RS - 232串口连接的传感器。
头两栏为了给用户输入，第三个为了在第一时间内监测传感器的参数，某些参数可以通过其他屏幕定制的程序和从PC 到传感器的命令更改。参数可以被用户通过以下方面来改变输入：
•继电器触点可设定为NO （常开）或数控（通常关闭）。
•中继功能可设定警报或设定点。
•温度单位可以改变由摄氏度至华氏度，反之亦然。
•显示器和模拟输出模式可以改变的智能传感器，再加上一两色的容量。
•激光（如传感器配有激光瞄准）可以开启或关闭。
•毫安输出设置和范围，可作为自动进程触发或警报。
•发射率（1色）或斜率（两色）比热值可设定。发射率和斜率值一般金属和非金属材料，并说明如何确定发射和斜坡，通常包含在传感器中。
•信号处理定义的温度参数返回，平均返回一个对象的平均气温在一段时间内; 峰值举行返回一个对象的最高温度可能在一段时间内或由外部触发。
•音响报警/劳报警可设定警告不当温度的变化，在一些过程线，这可能是引发打破在一个产品或故障加热器或冷却器的内容。
•衰减表明报警并关闭设置双色比智能传感器，在这个例子中，如果镜头是95％遮蔽，报警警告说温度的结果可能是失去准确性（称为“肮脏的窗口”报警）。95％以上可以默默无闻的触发一个自动关机的进程。
1.2 智能红外传感器的应用
智能型红外传感器，可用于任何生产过程温度是至关重要的高品质的产品中。 红外温度传感器可以看到监控产品的各种热工前后和干燥前后的温度。智能传感器上配置一个高速多点网络（定义见下文），并从远程监控的计算机上独立寻址。各地的传感器测量的温度都可以以调查的数据单独或季度的绘制成图表，便于监测和温度数据过程的存档。使用远程处理功能，设置点、报警器、发射率、和信号处理，信息可以被
下载到每个传感器，其结果是更严格的过程控制。
1.3 远程在线寻址
在一个持续的和图2相似的过程，智能传感器可以连接到一个或其他显示器。图表记录器和控制器分别在一个单独网络。该传感器可安排在多点或点对点配置，或者只是简单的独立。
在多点配置，多个传感器（多达32个在某些情况下）都可以联结到网络型电缆。每个传感器都拥有自己的“地址”，允许它分别设定不同的操作参数。由于智能传感器使用RS - 485接口或FSK 信号（频移键控）的通信，他们可以从控制室的电脑设置相当大的距离---多达1200米（ 4000英尺）的RS - 485接口，或3000米（一点零零零万英尺）的FSK 信号。有些程序使用RS - 232接口通信，但电缆的长度限制到100英尺。
在一个点对点的安装，智能传感器可以连接到图表记录、过程控制器、显示器、以及控制计算机。在这种类型的安装，数字通信可结合毫安电流回路作为一个完整的全方位的进程通信软件包。
但是，有时专门的程序得需要专门软件。一个壁纸制造商可能需要一系列的传感器编程来检查休息和眼泪沿着整个新闻界和涂层运行，但每个地区都有不同的环境和地表温度，如果发现表面的不正常现象，每个传感器必须触发警报。例如为了满足客户商具体的要求，工程师们可以使用出版协议数据编写自己的程序。这些自定义程序可以远程在飞虫身上安装传感器而不用关闭生产线。
2 刻度的标定和传感器的升级
无论是使用多点、点对点、或单一的传感器网络，工艺工程师需要适当的软件工具在自己的个人计算机上来校准、配置、监控和升级这些传感器。简单易于使用的数据采集、配置和实用程序通常是智能传感器套件购买时的一部分，或自定义的软件都可以使用。
与外地校准软件相比，智能传感器是可校准的。新的参数直接下载到传感器的电路和传感器的当前参数被保存和存储为计算机数据文件，以确保完整记录校准和/或参数的变化保留。一套校准技术，可以包括单点偏移和两到三点的可变温度：
•单点抵消 如果一个单一的温度在特定的过程中使用，传感器的读数需要重置，使其符合一个已知温度，单点偏移校准应使用。这个偏移将适用于所有温度在整个温度范围内工作。例如，如果一个已知的温度沿一个浮动的玻璃生产线是1800°F ，智能传感器或一系列的传感器，都可以校准那个温度。
•两点 如果传感器的读数必须符合两个特定的温度，这两个点在校准图3所示应选择。这种技术使用校准温度来计算增益和偏移是适用于所有在整个温度范围内的温度。
•三点变温度 如果这一进程具有广泛的温度范围，传感器的读数必须符合三个具
体温度，最好的选择是3点变温度校准。这种技术使用校准温度计算两个收益和两个偏移。第一增益和偏移适用于所有低于中点温度并在第二盘以上所有的中点的温度。三点校准和多单双点相比不太常见，但偶尔制造商需要执行此技术，以满足特定的标准。
现场校准软件还允许使用常规诊断方法，包括被运行在智能传感器上的电源电压和中继试验。结果让工艺工程师知道传感器的效果最佳，并在其做出一些必要的故障排除更加容易。
3 结尾
新一代的智能红外温度传感器要求工艺工程师必须跟上新的生产技术和产量增加所带来的变化。他们现在可以配置尽可能多的传感器来满足他们特殊控制过程的需要并且延长这些传感器寿命，远远超出先前的“不聪明”的设计。由于生产速度提高，设备停机时间必须减少。通过尽可能的监测设备和微调温度变量而无需关闭的进程，工程师们可以保持高效率的过程和提供高质量的产品。智能红外传感器的数字化处理组件和通讯能力提供一定程度的到现在都没有实现的灵活性、安全性和易用性。
红外线（ IR ）辐射是电磁波谱，其中包括无线电波、微波、可见光和紫外线，以及伽马射线和X 射线。IR 是在可见部分的频谱和无线电波之间的。红外波长通常以微米表示并且光谱范围由0.7至1000微米，只有0.7-14微米波段用于红外测温。
采用先进的光学系统和探测器，非接触式红外温度计就可以专注于几乎任何部分或0.7-14微米波段的部分。因为每一个对象（除黑体）排放量的最佳红外能量在某一特定点沿线的红外波段，每个过程可能需要独特的传感器模型与具体的光学和探测器类型。例如，一个传感器，一个狭窄的集中在3.43微米的频谱范围适合用于测量表面温度的聚乙烯和相关材料。一个传感器设在5微米是用来衡量玻璃表面。 光传感器用于金属和金属箔片。更广泛的光谱范围内用来衡量温度较低的表面，如纸、纸板、聚、和铝箔复合材料。
一个对象通过它的温度来体现排放红外能量增加还是减少。它是发出能量，以目标发射率来测量，那表明了一个物体的温度。
发射率是一个术语，用于量化能源发光特性不同的材料和表面。红外传感器具有可调发射率设定，通常是从0.1到1.0，使准确的测量的几个表面类型的温度。
发出的能量来自于一个对象，并通过其光学系统达到了红外传感器，其重点在能源上的一个或多个光敏探测器。然后探测器的红外能量转换成电信号，而这又是转换成温度值基于传感器的校准方程和目标的发射率。这一温度值可显示在传感器，或在一种智能传感器转换成数字输出，并显示在计算机终端。
Smart Infrared Sensors
K eeping up with continuously 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 become 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, as well as leading-edge digital circuitry. Chief among these tools, though, is the next generation of IR thermometers—the smart sensor.
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 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 manufacturing floor and computers in the control room (see Photo 1). And because the circuitry is smaller, the sensors are smaller, simplifying installation in tight or awkward areas. Integrating smart sensors into new or existing process control systems offers an immediate advantage to process control engineers in terms of providing a new level of sophistication in temperature monitoring and control.
Integrating Smart Sensors into Process Lines
While the widespread implementation 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 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, and, in some cases, be very dangerous. Upgrading a sensor usually required buying a new unit, calibrating it to the process, and installing it while the process line lay inactive. For example, some of the sensors in a wire galvanizing plant used to be mounted over vats of molten lead, zinc, and/or muriatic acid and accessible only by reaching out over the vats from a catwalk. In the interests of safety, the process line would have to be shut down for at least 24 hours to cool before changing and upgrading a sensor.
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 into 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 fluctuates, or the process itself undergoes changes in type, thickness, or temperature, all a process engineer needs to do is customize or restore saved settings at a computer terminal. If a smart sensor fails due to high ambient temperature conditions, a cut cable, or failed
components, its fail-safe conditions engage automatically. The sensor activates an alarm to trigger a shutdown, preventing damage to product and machinery. If ovens or coolers fail, HI and LO alarms can also signal that there is a problem and/or shut down the line.
Extending a Sensor’s Useful Life
For smart sensors to be compatible with thousands of different types of processes, 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, and/or utility software from the sensor manufacturer.
Another benefit of owning a smart sensor is that its firmware, the software embedded in its chips, can be upgraded via the communications link 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.
The Raytek 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 enclosures that can be mounted away from high ambient temperatures.
(see Photo 1). Clicking on a sensor window displays the configuration settings for that particular sensor. The Windows graphical interface 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 information comes from the sensor by way of the RS-485 or RS-232 serial connection.
The first two columns are for user input. The third monitors the sensor’s parameters in real time. Some parameters can be changed through other screens, custom programming, and direct PC-to-sensor commands. Parameters that can be changed by user input include the following:
∙ Relay contact can be set to NO (normally open) or NC (normally closed).
∙ Relay function can be set to alarm or setpoint.
∙ Temperature units can be changed from degrees Celsius to degrees Fahrenheit, or vice versa.
∙ Display and analog output mode can be changed for smart sensors that have combined one- and two-color capabilities.
∙ Laser (if the sensor is equipped with laser aiming) can be turned on or off.
∙ Milliamp output settings and range can be used as automatic process triggers or alarms.
∙ Emissivity (for one-color) or slope (for two-color) ratio thermometers values 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.
∙ Signal processing defines 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.
∙ 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.
∙ 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 as a “dirty window” alarm). More than 95% obscurity can trigger an automatic shutdown of the process.
Using Smart Sensors
Smart IR sensors can be used in any manufacturing process in which temperatures are crucial to high-quality product.
Six IR temperature sensors can be seen monitoring product temperatures before and after the various thermal processes and before and after drying. The smart 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 sequentially; the data can be graphed for easy monitoring or archived to document process temperature data. Using remote addressing features, set points, alarms, emissivity, and signal processing, information can be downloaded to each sensor. The result is tighter process control.
Remote Online Addressability
In a continuous process similar to that in Figure 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 alone.
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 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-485, or 3000 m (10,000 ft.) for FSK. Some processes use RS-232 communications, but cable length is limited to
In a point-to-point installation, smart sensors can be connected to chart recorders, process controllers, and 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.
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, but 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 programs using published protocol data. These custom programs can remotely reconfigure sensors on the fly —without shutting down the process line.
Field Calibration and Sensor Upgrades
Whether using multidrop, point-to-point, or single sensor networks, process engineers need 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 sensor package when purchased, or custom software can be used.
With field calibration software, smart sensors can be calibrated, new parameters downloaded directly to the sensor’s circuitry, and the 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 two- and three-point with variable temperatures:
• 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 temperature, 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°F, the smart sensor, or series of sensors, can be calibrated to that temperature.
• Two-point. If sensor readings must match at two specific temperatures, the two-point calibration shown in Figure 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.
• Three-point with variable 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 technique 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 midpoint. Three-point calibration is less common than one- and two-point, but occasionally manufacturers need to perform this technique to meet specific standards.
Field calibration software also allows routine diagnostics, including power supply voltage and relay tests, to be run on smart sensors. The results let process engineers know if the sensors are performing at their optimum and make any necessary troubleshooting easier.
Conclusion
The new generation of smart IR temperature sensors allows process engineers 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 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 without shutting down a process, engineers can keep the process efficient and the product quality high. A smart IR sensor’s digital processing components and communications capabilities provide a level of flexibility, safety, and ease of use not achieved until now.
How Infrared Temperature Sensors Work
Infrared (IR) radiation is part of the electromagnetic spectrum, which includes radio waves, microwaves, visible light, and ultraviolet light, as well as gamma rays 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 micron band is used for IR temperature measurement.
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 every 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 example, a sensor with a narrow spectral range centered at 3.43 microns is optimized for measuring the surface temperature of polyethylene and related materials. A sensor set up for 5 microns is used to measure glass surfaces. A 1 micron sensor is used for metals and foils. The broader spectral ranges are used to measure lower temperature surfaces, such as paper, board, poly, and foil composites.
The intensity of an object's emitted IR energy increases or decreases in proportion to its temperature. It is the emitted energy, measured as the target's emissivity, that indicates an object's temperature.
Emissivity is a term used to quantify the energy-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 emitted 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, which is in turn converted into a temperature value based on the sensor's calibration equation and the target's emissivity. This temperature value can be displayed on the sensor, or, in the case of the smart sensor, converted to a digital output and displayed on a computer terminal。