(www.oeiweb.omron.com) details two of the trends. One is sensors with embedded “and/or” intelligence; the other is the ability of sensors to communicate data upstream. Examples of the latter include photosensors communicating with one another, or a safety light-curtain talking via a network to a controller. Omron is developing a smart laser sensor with a 20-micron resolution for use in profile inspections, Suffi says. “It can look at an object, analyze the shape of it and compare it to a known shape.”
Broader functionality depicts Pepperl+Fuchs Inc. (www.pepperl-fuchs.com) photoelectrics developments. One example is its 4-in-1 output, a term the company started using in November 2004, says Jeff Allison, a product manager in the company’s North American headquarters, in Twinsburg, Ohio. It allows users to plug devices into either current-sourcing (positive-negative-positive, or PNP) or current-sinking (negative-positive-negative, or NPN) transistor outputs, in either the normally open or normally closed positions—automatically determining the proper output. “The only difference between PNP and NPN is how the technician installs the sensor and connects it to the load,” explains Ed Meyers, also a Twinsburg-based Pepperl+Fuchs photoelectrics product manager.
The company is also working to enhance background suppression, which is sensing with photoelectrics out to a specified distance, but detecting nothing beyond that. “Background suppression is basically a variant on diffused sensing,” Meyers says. “Diffused sends a light beam. If a target gets in front of it, a light beam is bounced back.” The reason to cut off sensing at a preset distance is to eliminate false positive readings caused by such factors as a shiny panel behind a conveyor line. Both diffuse and background suppression sensors use only one device to send and receive the light signal, making setup easier than a through beam style sensor that requires separate sender and receiver.
Ultra-miniature describes an advance which comes through Plymouth, Minn.-based Banner Engineering Corp.’s (www.bannerengineering.com) just-released, pre-programmed World-Beam Q12 Series photoelectric sensors. “A production designer can mount it in confined places, such as the inside wall of a conveyor. That’s handy for the obvious reasons, but also because it is small enough to be tucked inside a machine where it won’t be bumped or tampered with,” says Mike Dean, director of Banner‘s research-and-development product planning.
Micro-sized characterizes Uprox+, a 40-millimeter cube-shaped inductive proximity switch that Turck Inc. (www.turck.com) was scheduled to introduce in the United States in late April. While regular proximity switches have copper wire coiled around a ferrite core, the Turck product has a patented multi-coil technology but no ferrite core, says Eric Henefield, a Sensors Division product manager in Turck’s North American headquarters in Plymouth, Minn.
Unlike regular proximity switches, which are standardized to detect mild steel at some rated range, such as 75 mm, Uprox+ adapts itself to what it is detecting. “It senses all metals at the same range. The sensor can be set a fixed distance,” he says.
Where is sensing technology headed? “The capabilities of sensors are coming to the point where the machine is basically managing itself,” Omron’s Suffi says.
C. Kenna Amos, [email protected], is an Automation World Contributing Editor.
