One recent shift concerns used-everywhere, been-around-forever, application-specific integrated circuit (ASIC) technology—specifically in diffuse sensors, states Lonnee Vandenheuvel, industrial-sensors division manager for components vendor Sick Inc. ( www.sickusa.com), Minneapolis. Two others trends he mentions include remote configuration of low-end sensors, and rugged sensors that can live in harsh washdown environments.
 
ASIC technology advances allow diffuse sensors to now “reliably ignore backgrounds,” he claims. Some typical ones that Vandenheuvel points out include equipment parts, reflective vests from people walking by and, “most importantly,
the fact that parts are moving in the background.” One obvious use is packaging-equipment applications, where the sensor gives yes/no detection. “This technology helps in multi-colored objects. As the object passes by, you don’t get any ‘chatter.’ So when products change, the sensor doesn’t need readjustment,” he explains.

End-users’ requests inspired the second development on Vandenheuvel’s list: “Configure a relatively low-end sensor and do that remotely.” This functionality allows end-users to access data from the sensor via IO-Link, a multi-vendor-created smart point-to-point communications protocol from the IO-Link Consortium ( www.io-link.com), Karlsruhe, Germany.

The protocol is compatible with existing input/output (I/O) standards. “What’s especially nice is that it doesn’t require special wiring for retrofit. For new equipment, it’s nice because it’s the traditional wiring/connectivity scheme,” Vandenheuvel says. That means, he explains, that end-users can use IO-Link sensors and I/O points rather than reconfiguring for a fieldbus.

Commenting about IO-Link, Jeff Himes suggests that “more innovative connectivity and communication networks seem to be leading the major shifts in the industry vs. the sensors themselves.” The inductive sensor product specialist with Balluff Inc. ( www.balluff.com), an automation components supplier in Florence, Ky., Himes also emphasizes that the IO-Link expansion module creates a seamless, highly transparent bridge to the Profibus network, making retrofitting or expansion simple. Sensor hubs can be used to expand the standard I/O capability, he adds. “Or IO-Link-compatible sensors with built-in diagnostics can be connected directly to the expansion module.”
 
Rugged for longer life

More rugged sensors in harsh environments complete Vandenheuvel’s list. “We didn’t realize until fairly recently that some end-users thought that they had no other option than to replace the sensors frequently,” he notes. But use of stainless-steel housings with laser-etched information, rather than glued-on labels, and even an improved construction process “allow longer-lived instruments,” he remarks. Up-front costs of these more-rugged devices are higher, though, he notes, but so is return on investment.

However, Himes observes that sensor materials “seem to be trending toward lighter alloys vs. stainless steel.” This is reflected, he believes, in increased use of Factor 1—or multi-metal-sensing—sensors. “They have the capability to sense ferrous or non-ferrous metals at virtually the same sensing distance.” He adds that use of block-style-housing models is also increasing. “They allow for a larger coil design/longer sensing range in a much more compact package.”

Himes suggests a fourth technology trend: the “dramatic boost in sensor miniaturization.” As the economy has begun its apparent recovery, miniature proximity sensors have been one of Balluff’s strongest growth segments, he reveals. Mini-sensors will give OEMs the ability to produce smaller, lighter, more efficient machinery, he believes. “The low mass of these mini-sensors also enables abrupt acceleration and deceleration on highly dynamic, fast-moving equipment without adding excessive inertial load.”

C. Kenna Amos , ckamosjr@earthlink.net, is an Automation World Contributing Editor.

Sick Inc.
www.sickusa.com

IO-Link
www.io-link.com

Balluff Inc.
www.balluff.com

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