In today’s competitive manufacturing environment, the name of the game is increased throughput. Unprecedented global competition means that industrial manufacturing machinery must be able to run better (faster, longer, hotter, etc.) and more reliably than ever before.
Consequently, sensors used on these machines need to be able to withstand sometimes punishing conditions – high shock loads, elevated operating temperatures, moisture, dirt – you name it.
Choosing the right sensor involves comparing the demands of the application to characteristics of the sensor. For example:
High Shock: Applications that generate a lot of shock (think die-casting or sawmill equipment) require sensors that can “take a licking and keep on ticking”. For example, linear position sensors using a laser-etched glass scale are certainly very accurate, but may not be such a good choice in such an application. You might be better off with a magnetostrictive sensor designed to reside in the protective confines of a hydraulic cylinder.
Highly Cyclical, Repetitive Motion: Machinery that cycles back and forth all day, everyday, demands a sensor that can withstand the daily grind. Some linear position sensors are better-suited than others. For example, resistive linear potentiometers, while fairly inexpensive, operate by means of a wiper slider back and forth on a resistive element. Since there is mechanical contact involved, there is eventually going to be wear, performance degradation, and/or outright failure. A better choice for these applications would be a sensor that utilizes a non-contact sensing technology.
Temperature Extremes: Don’t forget to consider where your sensor has to live. Some applications (steel mills,die-casting,etc.) subject sensors to high temperatures, while some machinery lives in the great outdoors (railroad maintenance equipment, for example), and is subject to extremes ranging very cold to very hot, possibly in the same day.
Listed above are but a few of the many demanding conditions under which machinery is expected to operate. It is important to choose a sensor that will handle everything that an application is likely to throw at it.