Do industrial sensors measure up?

It seems that industrial sensors are still awaiting innovation. Senior Tech Editor Rich Merritt reports on who's dominating the sensor business in this Product Roundup of new sensing devices.

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By Rich Merritt, Senior Technical Editor

HISTORICALLY, companies in the sensor business made a nice living by specializing in one or more areas, and producing a quality product for the money. For example, few were as successful as the Rosemount DP flow meter, which became the world standard, but many sensor brands and companies became household words. A glance at the CONTROL DESIGN Readers’ Choice Awards will show you the same companies dominating the sensor business with the same products, year after year.

Many of the better-known product and vendor names have been absorbed by acquisitions and mergers, but smart buyer companies keep the old names and keep the products current and competitive, so the same products continue to dominate.

Things are changing, however. Innovation is dying off, as companies try to survive in these tough economic times by competing on price. As a Frost & Sullivan ( study on industrial sensors puts it, “With the majority of offerings being similar, price emerges as the chief driving factor. To compete almost exclusively on the basis of price, manufacturers have been compelled to concentrate on reducing costs.” That means cost cutting is in, R&D is out, and products no longer stay current and competitive.

Innovation would imply the adoption of new technologies, such as smart sensor capabilities, wireless sensors, nanotechnology, plug-and-play (IEEE 1451.4) sensors, and so on, but they don’t seem to be coming to market. We do see plenty of sensors that are getting smarter, as you will see in the roundup below. 

The roundup has sensors that can be remotely calibrated, have many user-selectable features, tune themselves, adjust their own power requirements, and are immune to industrial hazards. These advances are mostly enhancements to existing products, and often don’t add to the basic cost of the sensor. One such sensor, in fact, costs 10% less than the product it is replacing.

But these are not necessarily “smart sensors,” nor do they embody the use of new technologies. The vendors are staying current and competitive with existing technology, but innovation goes out the window. 

The definition of smart sensor varies from vendor to vendor. Some think they are IEEE 1451.4 sensors, others think they are anything with a communications link. According to Frost & Sullivan, a true “smart sensor” has many digital components, including microprocessors, a web server, communications ports, memory, digital outputs, and so on, and is typically priced almost twice as high as the equivalent analog sensor. “The cost of installation is extremely high,” F&S says, “especially in the case of in-plant installation.” 

The true smart sensor would be a device that does more than current products, costs less, and is easy for a machine builder to install. We can’t wait for such sensors. Meanwhile, browse through our selection of new sensor products and you’ll see that some companies are on the right track, whether they have smart sensors or not. 

Product Roundup of Sensor Devices

Take the Cable and Go Home
To help prevent unauthorized changes, the Telemecanique XUN “teachable” photoelectric sensor has a removable push button cable. The cable is used to program the sensor to operate in any of four sensing modes--background suppression, proximity diffuse, polarized retro-reflective and thru-beam. The sensing range of the sensor is 4.7 in. to 49.2 ft, depending on mode and can be panel-mounted or 18 mm thread-mounted. Schneider Electric; 704/916-6173;

Photoelectric Sensors Get Flexible
Tru-Vue photoelectric sensors have flexible side-mounts or nose-mounts, can be surface mounted, or can be mounted like 18 mm cylindrical sensors via the threaded nose. Each has highly visible 360 deg. LEDs for status indication in all directions. Available sensing modes include background suppression, diffused, retro-reflective, thru-beam and fiberoptic. Multiple electrical connection options are available. Tamper-proof models are available to eliminate sensitivity adjustments by unauthorized personnel. Pepperl+Fuchs; 330/486-0001;
Programmable Sensor Monitors Motion
The Gemco 955 Brik Gen III programmable linear displacement transducer detects movement to 0.001 in. A simple programming unit provides calibration for changing the setting of zero and span. Its tri-color LED visual indicator verifies optimal magnet positioning, confirms active zones, and provides self-diagnostics of LDT functions. The sensor is available in a variety of transducer outputs and can be ordered in lengths to 180 in. Ametek; 800/635-0289;

On Vibration Watch
Model 685A01 electronic vibration switch provides early warning of machine deterioration and will initiate shutdown when the trip level is exceeded, preventing catastrophic damage and expensive repairs. It has an explosion-proof housing, Form C SPDT relay, adjustable trip point, local and remote reset, and continuous or latch relay operation. Operating range is 0-10 g from 10-1,000 Hz, suitable or predictive maintenance on rotating equipment. PCB Piezotronics; 800/959-4464;

Vibration Transmitter in the Loop
The HI 5701VTE loop-powered vibration transmitter provides a 4-20 mA output proportional to vibration amplitude levels of 0-1, 0-2, or 0-3 ips peak--suitable for monitoring vibration levels on rotating or reciprocating equipment. The sensor has non-polarity wiring and a power supply requirement of 10 VDC, and provides both 4-20 mA and buffered outputs. Hardy Instruments; 800/821-5831; 

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