Non-contact sensor market touched by innovations

Sensors such as inductive proximity, capacitive proximity, photoelectric and ultrasonic are being used in many applications for which they were never considered previously. These noncontact sensors are available with a variety of output configurations, such as normally-open (NO) and normally-closed (NC) contact configurations, as well as analog output configurations.


Sensors such as inductive proximity, capacitive proximity, photoelectric and ultrasonic are being used in many applications for which they were never considered previously. These noncontact sensors are available with a variety of output configurations, such as normally-open (NO) and normally-closed (NC) contact configurations, as well as analog output configurations.

An inductive proximity sensor with an analog output, for example, could take the place of a traditional limit switch monitoring a cable pulley system (Fig. 1). The analog output could detect when the cable is starting to stretch and signal a maintenance person so preventive action can be taken instead of experiencing an unscheduled shutdown. Conversely, a limit switch may detect only when the cable is out of specification, or the switch may fail due to the wear and tear of being in physical contact with the cable.

Smaller is better

A recent advancement for noncontact sensors is the of "thin-is-in" concept. OEMs and end users are both looking for smaller and more accurate sensors. Market trends show that shape and size does matter. New technologies for the sensing circuitry as well as moldings for the housings are breaking application barriers.

New sensor features are creating another accelerating trend. Proximity sensors are starting to incorporate status LEDs that are visible 360 deg around the sensor (Fig. 2). Sensor manufacturers use LEDs to provide more information than just sensing indication. For example, a status LED can pulse to indicate a weak detection signal, possibly caused by a sensor coming out of adjustment, or by a foreign object such as grease covering the sensor surface.

Advancements such as these will enable users to diagnose possible problems. A trained maintenance person can observe the pulsating LED and take action before a process shuts down unnecessarily.

It's what's inside that counts

Sensors are taking their shape from the inside and changing their outside dimensions and mounting options. Sensor manufacturers are incorporating such technologies as application-specific integrated circuits (ASICs) to drive down the size and cost, and increase ease of use of sensors. Using ASIC technology, fewer components are required to control the sensing circuit. Combining a large number of components onto a single integrated chip allows sensors to achieve greater sensing distances — up to three times that of existing sensors — in a package smaller than 8 mm in diameter.

ASIC technology also increases sensor precision. Sensor manufacturers do not have to rely on special machines to "calibrate" a trimming resistor in order for each sensor to be within specification. The ASIC technology allows the sensors to be calibrated digitally with programming devices.

Sensors incorporating ASIC technology can be manufactured at a reduced cost by lowering the number of components needed to control the sensor and the reduction of labor required to assemble the units. Thus, these sensors cost less for both OEM and user. Sensor manufacturers can lower their inventory overhead because the sensors can be assembled quickly.

As the components of sensors shrink, the sensor housings become smaller. Current production methods such as gaskets, glue and epoxies are no longer the best choices. Designers now rely on such techniques as overmolding and ultrasonic welding. This type of fabrication provides tight seals and the rugged packaging needed in industrial environments.

Sensor types

With more functionality in a smaller package, those who used 30 mm sensors can now use 18 mm sensors; and the 18 mm sensors can be replaced with 12 mm units. The 12 mm sensors have become one of the most popular sizes, but now that 8 mm inductive proximity sensors have sensing distances up to 3 mm shielded and 4 mm unshielded, their market share is starting to increase.

Photoelectric sensors

The size of photoelectric sensors is also decreasing . The trend for these sensors is moving from the big rectangular-style package to a much more compact style in both miniature rectangular and round configurations. Benefits to machine builders include the ability to locate the sensors closer to their targets in order to use the full strength of the optics.

Where certain applications demanded installation of a sensing head connected to cables and a separate processing unit, smaller sensors can be mounted in tight and obscure places. In addition, the compact size still maintains the high reliability and durability needed for the industrial market.


The use of lasers in sensors offers great improvements in precise position detection, counting and inspection applications (Fig 3). These sensors are able to detect position changes in distances as small as the thickness of a business card. This helps users dramatically reduce process errors and prevent defective products from entering the marketplace.

Laser technology is also decreasing manufacturing costs and sale prices, providing inexpensive solutions to sensing needs that could not be met in the past.

Ultrasonic sensors

Ultrasonic sensors also are becoming smaller and more cost effective. They have a great advantage over typical proximity and photoelectric sensors because they have very good sensing ranges and are not as affected by dust or other environmental factors. Ultrasonic sensors are designed so there is almost no dead zone in the detection area.

Another advantage is that one ultrasonic sensor can be used for many materials without extra setup or sensing concerns. For example, an ultrasonic sensor can be used to detect a clear plastic film and the same sensor can then detect a red plastic film if required by the process. This type of dynamic operational change could be difficult if a standard clear-object-style photoelectric sensor were used.

The Top Plant program honors outstanding manufacturing facilities in North America. View the 2015 Top Plant.
The Product of the Year program recognizes products newly released in the manufacturing industries.
Each year, a panel of Control Engineering and Plant Engineering editors and industry expert judges select the System Integrator of the Year Award winners in three categories.
Doubling down on digital manufacturing; Data driving predictive maintenance; Electric motors and generators; Rewarding operational improvement
2017 Lubrication Guide; Software tools; Microgrids and energy strategies; Use robots effectively
Prescriptive maintenance; Hannover Messe 2017 recap; Reduce welding errors
The cloud, mobility, and remote operations; SCADA and contextual mobility; Custom UPS empowering a secure pipeline
Infrastructure for natural gas expansion; Artificial lift methods; Disruptive technology and fugitive gas emissions
Mobility as the means to offshore innovation; Preventing another Deepwater Horizon; ROVs as subsea robots; SCADA and the radio spectrum
Research team developing Tesla coil designs; Implementing wireless process sensing
Commissioning electrical systems; Designing emergency and standby generator systems; Paralleling switchgear generator systems
Natural gas engines; New applications for fuel cells; Large engines become more efficient; Extending boiler life

Annual Salary Survey

Before the calendar turned, 2016 already had the makings of a pivotal year for manufacturing, and for the world.

There were the big events for the year, including the United States as Partner Country at Hannover Messe in April and the 2016 International Manufacturing Technology Show in Chicago in September. There's also the matter of the U.S. presidential elections in November, which promise to shape policy in manufacturing for years to come.

But the year started with global economic turmoil, as a slowdown in Chinese manufacturing triggered a worldwide stock hiccup that sent values plummeting. The continued plunge in world oil prices has resulted in a slowdown in exploration and, by extension, the manufacture of exploration equipment.

Read more: 2015 Salary Survey

Maintenance and reliability tips and best practices from the maintenance and reliability coaches at Allied Reliability Group.
The One Voice for Manufacturing blog reports on federal public policy issues impacting the manufacturing sector. One Voice is a joint effort by the National Tooling and Machining...
The Society for Maintenance and Reliability Professionals an organization devoted...
Join this ongoing discussion of machine guarding topics, including solutions assessments, regulatory compliance, gap analysis...
IMS Research, recently acquired by IHS Inc., is a leading independent supplier of market research and consultancy to the global electronics industry.
Maintenance is not optional in manufacturing. It’s a profit center, driving productivity and uptime while reducing overall repair costs.
The Lachance on CMMS blog is about current maintenance topics. Blogger Paul Lachance is president and chief technology officer for Smartware Group.
The maintenance journey has been a long, slow trek for most manufacturers and has gone from preventive maintenance to predictive maintenance.
Featured articles highlight technologies that enable the Industrial Internet of Things, IIoT-related products and strategies to get data more easily to the user.
This digital report will explore several aspects of how IIoT will transform manufacturing in the coming years.
Maintenance Manager; California Oils Corp.
Associate, Electrical Engineering; Wood Harbinger
Control Systems Engineer; Robert Bosch Corp.
This course focuses on climate analysis, appropriateness of cooling system selection, and combining cooling systems.
This course will help identify and reveal electrical hazards and identify the solutions to implementing and maintaining a safe work environment.
This course explains how maintaining power and communication systems through emergency power-generation systems is critical.
click me