测控技术与仪器毕业论文外文翻译(编辑修改稿)

测控技术与仪器毕业论文外文翻译(编辑修改稿)内容摘要：

ettings at a puter terminal. If a smart sensor fails due to high ambient temperature conditions, a cut cable, or failed ponents, its failsafe 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 patible 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 munications link to revisions as they bee 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 2color ratio IR thermometers that can be worked with up to 32 smart sensors. Available models include both integrated units and fiberoptic 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 es from the sensor by way of the RS485 or RS232 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 PCtosensor mands. 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 bined one and twocolor 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 onecolor) or slope (for twocolor) ratio thermometers values can be set. Emissivity and slope values for mon 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。 peakhold 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 twocolor 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 highquality product. Six IR temperature sensors can be seen monitoring product temperatures before and aft。