It's Sensible to Use Sensors

Choose the right ones and you’ll protect, maybe enhance, your company’s bottom line. With today’s economy, that benefit matters.

General sensor categories include contact and non-contact. Contact sensors include mechanical devices such as limit switches, explains Rick Bondy, industrial sensors product manager with automation components supplier Sick Inc. (www.sickusa.com), Minneapolis. “Non-contacts—photoelectric, capacitive, ultrasonic, magnetic, inductive and vision—generally allow end-users to detect smaller targets at longer distances; different types of target materials; and not only presence, but also distance,” Bondy continues.

Through sensors, end-users can reduce part defects by up to 15 percent and/or eliminate product containments or recalls, states Mark Sippel, product manager, object identification, with Balluff Inc. (www.balluff.com/Balluff/us), another automation vendor in Florence, Ky. And now, with sensors, error-proofing and even Six-Sigma sensing strategies make sense for end-users, he adds.

High-accuracy distance-measurement photoelectric sensors help meet end-users’ expectations for error-proofing applications. That improves processes and product-quality inspections, Bondy states. One example of proactive, cost-effective thinking for photoelectrics is background suppression (BGS). He calls improvements to BGS a new innovation that is “vastly improving sensing capabilities in factory and logistics automation.”

The technology eradicates changeover time “because it detects various materials—regardless of color, print and reflectivity—at nearly identical distances,” contends Jeff Allison, product manager with Pepperl+Fuchs Inc. (www.am.pepperl-fuchs.com), a Twinsburg, Ohio, vendor. A significant advantage he sees is this technology’s use where “the object to be detected changes day-to-day or even shift-to-shift.” Advantage arises because BGS offers “consistent reliable sensing without any need for readjustments or sensor retuning.”

Balluff’s Roger Altendorf calls BGS a “go to” photoelectric-sensor technology. Another “go to” is self-contained thru-beam sensors, he says. Both types “are easier to set up and more reliable by the nature of their operation, so less-experienced users can apply them with higher success than standard diffuse or fiber-based thru-beam technologies,” remarks Altendorf, a photoelectric-sensor product specialist. The financial bottom line he’s seen is that end-users may cut costs “as much as 20 percent” with those two technologies.

10 times faster

Vision-based sensor technology is also a more viable and low-cost solution, Altendorf suggests. These sensors provide solutions that produce faster line changeover and flexible, self-contained error-proofing. Some new technology may be “two to 10 times faster than inflexible sensor arrays or more complex vision sensors,” he remarks. That new technology may also give “as much as 48 percent lower cost than more traditional ‘vision sensors’ and significantly less than manual inspection stations.”

New technology advances in capacitive sensors help reduce end-user and original-equipment-manufacturer engineering and assembly costs, comments Bjoern Schaefer, a Balluff capacitive-sensors product specialist. “Specifically, by not placing a sensor in a fluid tank [as with more traditional float switches], there is no wear or maintenance required.” That will eliminate sensor damage, especially when exposed to harsh environments such as caustics. Another benefit Schaefer notes is avoidance of false triggering of conditions.

But with all these advances, there looms a negative trend for sensors. Bondy calls it “commoditization.” An example he cites is the introduction, using inductive technology, of several competitive products having the same performance specifications and mounting matrix. “This drives the products to be commodity-based solutions that make it more difficult for some manufacturers to show value in their product.”

Another negative trend Craig Eilmann sees is today’s economy-driven undereducation of end-users. “Companies are running lean with minimal personnel. Subsequently, they’re reluctant to allow their person the time to learn new product technologies,” notes this senior product specialist with vendor Schneider Electric’s Sensor Competency Center (www.sesensors.com), Dayton, Ohio.

C. Kenna Amos, [email protected], is an Automation World Contributing Editor.