A Bold New Era in Instrumentation
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Intelligent wireless sensing networks are using a new breed of rugged, accurate sensors to provide near real-time, remote monitoring of the harshest environments.

By Mark Shortt
Editorial Director, Design-2-Part Magazine

In his 1997 essay, "Sensors: The Next Wave of Infotech Innovation," Paul Saffo, director of the Institute for the Future (IFTF) in Palo Alto, Calif., predicted big changes resulting from our use of sensors, saying that "the impact of sensors will be as surprising in the decade ahead as that of microprocessors in the 1980s and lasers in the 1990s." In his essay, Saffo delivered some interesting insights on how innovations from different disciplines are converging to yield a whole that is truly greater than the sum of its parts.

"Such new devices—cheap, ubiquitous, high-performance sensors—are going to shape the coming decade," wrote Saffo. "In the 1980s, we created our processor-based computer 'intelligences.' In the 1990s, we networked those intelligences together with laser-enabled bandwidth. Now in the next decade, we are going to add sensory organs to our devices and networks. The last two decades have served up more than their share of digital surprises, but even those surprises will pale beside what lies ahead. Processing plus access plus sensors will set the stage for the next wave—interaction. By 'interaction' we don't mean just Internet-variety interaction among people—we mean the interaction of electronic devices with the physical world on our behalf."

It's clear that Saffo is on to something. Ten years after his prediction, sensors are making an impact in every conceivable industry, ranging from automotive safety to industrial process monitoring and liquid level measurement, to wireless temperature sensing in homes. The worldwide market for automotive sensors alone was estimated to be more than $10 billion in 2005, a figure expected to rise to $14.2 billion by 2010, according to a report published in 2005 by Business Communications Company, Inc., now known as BCC Research (www.bccresearch.com; Automotive Sensors report RGB-323).

Sensors perform a wide range of monitoring and data collection tasks necessary for measurement, analysis, and control of loads, force/impact, pressure, temperature, sound, moisture, and shock/vibration. Instruments today are increasingly relying on "smart sensors," used in wireless networks, to provide information for near real-time monitoring and control. Many of these sensors are multifunctional devices that offer greater design flexibility.

Wireless Data Acquisition System Offers Integral Interface to ICP® Sensors

Helping manufacturers see problems before they occur is what keeps the people of Oceana Sensor Technologies, Inc., up at night—even as their work gives customers peace of mind. Oceana Sensor Technologies, Inc., located in Virginia Beach, Va., is a manufacturer of OEM piezoelectric vibration sensors and smart wireless sensing systems for applications that include monitoring and control of manufacturing processes and machinery. By enabling manufacturers to know beforehand when their equipment or machinery is going to fail, Oceana's sensors and data collection tools allow companies to save tremendous amounts of time and money. In its sensor designs, the firm employs the latest piezoceramic technology to create rugged, shock-resistant, and fast-response sensors that achieve high resolution and sensitivity while operating in broad temperature and frequency ranges.

In addition to producing OEM piezoelectric vibration sensors, Oceana manufactures smart wireless sensing and networking systems that can enable what the company calls "true condition-based maintenance, proactive monitoring of machinery health, and significant reduction in unscheduled machinery maintenance and downtime." The company offers, under the Wireless e-Diagnostics® brand, products built upon the ICHM® 20/20 data acquisition and processing module that enable "near real-time remote monitoring of a wide variety of sensing parameters."

The ICHM® (Intelligent Component Health Monitor) 20/20 wireless data acquisition and processing module, built on Bluetooth® wireless technology for transducer area networking, is designed to serve in any type of monitoring and control application. A worldwide industry standard (IEEE 802.15) wireless communication network, provided by Bluetooth® wireless technology, facilitates interoperability with devices ranging from handheld computers to various wired or wireless network options. According to the company, the ICHM® family of products can be integrated with a variety of industrial buses and local area networks to "enable connectivity from component to enterprise around the globe."

Oceana Sensor is part of the PCB Group of companies, headed by PCB Piezotronics Inc., which introduced ICP® (Integrated Circuit Piezoelectric) instrumentation in the late 1960s. The ICP sensing technology, now a popular sensing protocol, was introduced to replace complicated and costly external-charge amplifiers with low-cost, internally-amplified pressure, force, and vibration sensors that are easy to operate. A key reason that ICP sensing technology was adopted so readily was the increased use of condition-based maintenance (CBM), the practice of performing maintenance on machinery based on its actual condition, rather than the number of hours it's been in service.

As the practice of CBM took hold, it saved costs by allowing machines to operate to their maximum useful life, eliminating the premature replacement of components and reducing unplanned downtime. And as a cost-effective component that was easy to use, the ICP accelerometer fit in well with the economic practicality of a changing industrial environment. Today, Oceana says, nearly every data-logger and signal analyzer in production is equipped with ICP power.

In May 2005, Oceana Sensor launched a version of its ICHM® 20/20 wireless data acquisition system that "offers direct interface to the world of ICP® sensing information." In other words, it is designed to interface with ICP® sensors directly, rather than through in-line signal conditioners. The ICP® power-equipped ICHM 20/20-HS 100-ICP offers plant maintenance officials the opportunity to convert legacy ICP accelerometer installations—locally connected to junction boxes for route-based collection—to remotely monitored points via 100-meter wireless Bluetooth® connectivity.

Said to be built for flexibility and connectivity, the ICHM 20/20-HS 100-ICP provides Bluetooth wireless communication to the host PC and uses Oceana's SHM® (System Health Monitor) software. To power the device, the ICHM 20/20-HS 100-ICP utilizes 12VDC line-power, supplied by either a 110VAC-to-12VDC converter or an appropriate DC-to-DC converter, the company says.

Oceana Sensor's wireless installations are used in industries where machinery health monitoring is critical, including military platforms, manufacturing operations, and power generation facilities.

Thermocouple Smart Sensor Operates as Part of Wireless Sensor Network

Monitoring of temperature in hazardous locations can be a challenging task. Sensicast Systems (Needham, Mass.), a provider of wireless sensor networks for industrial automation and monitoring, has introduced a sensor that makes it easier to do the job. The SensiNet® TECO-1021 Thermocouple Smart Sensor is reported to be a robust, wireless sensor that delivers accurate measurements from hazardous environments.

A wide variety of thermocouples can interface with the TECO-1021, said to be an intrinsically-safe wireless temperature monitoring device designed for use in Class 1 Div II hazardous locations. The device, which operates at 2.4GHz, and is FCC and CE approved, reports highly accurate (<±0.05%) and repeatable real-time temperature measurements to a central management application.

The TECO-1021 operates as a component of Sensicast SensiNet—described by the company as a self-configuring, self-healing, battery-operated wireless sensor network. It also integrates with the SensiNet Services Gateway, a fully self-contained network appliance with embedded connectivity and data-reporting functionality that manages the SensiNet network and integrates it with legacy systems; built-in Web 2.0 data visualization applications; and industry-standard communications protocols. The Thermocouple Smart Sensor, said to be easy to install, enables hands-free operation in environments where wired sensing is either impossible or impractical; in hazardous locations (steel and aluminum mills; oil and gas plants); and in food production and pharmaceutical manufacturing facilities.

In addition to supporting a wide range of thermocouple types, the TECO-1021 monitors temperatures ranging from -148ºF to +3000ºF. It features NEMA-4X rated housings, optional moisture-resistant enclosures, and an advanced radio design that provides reliable connectivity in harsh RF environments, the company says.

The SensiNet Services Gateway provides data access and external communications for SensiNet. It allows users to securely access and analyze, using a convenient browser interface, data collected by Smart Sensors. It also communicates sensor data directly to "dozens of industrial software applications."

SensiNet Services, launched by Sensicast in February, enables plant and facility managers to use the company's temperature- , energy- , and moisture-monitoring applications over the Internet, without having to locate the applications within their own network infrastructure.

"As the first totally integrated measurement system to combine the power of wireless sensor networking with the flexibility of Web-access, SensiNet Services lets manufacturers measure anything, from anywhere without wires," said Gary Ambrosino, CEO of Sensicast, in a statement announcing the launch.

Multi-purpose Wireless Sensor Provides Integrated Functionality

Another innovative sensor that operates within wireless protocols is the Chorus™ wireless sensor and condition monitoring technology from Solidica, Inc., Ann Arbor, Michigan. Currently undergoing field trials for a variety of military and commercial customers, the Chorus™ sensor is integrated into a compact, rugged package to measure system health parameters such as temperature, vibration, and three-dimensional acceleration. At the same time, it provides "integrated GPS and RFID functionality," according to Solidica, a company named one of the "Michigan 50 Companies to Watch" last month in an awards program sponsored by the Edward Lowe Foundation.

The Chorus device, winner of the Best of Sensors Expo 2006-Gold award, is said to instantly capture sensor input in the harshest environments, provide localized embedded signal processing, and transmit user-programmable alerts to Solidica's Pantheon™ sensor network, diagnostic, and telematics hardware. The flexible system operates within the framework of multiple commercially common wireless protocols, including the ZigBee and IEE 802.15.4 standards, using 2.4 GHz digital radio and microcontroller technology. According to Solidica, the Chorus device allows new or existing analog inputs to be directly connected, instantly transforming legacy vehicles, equipment, or shop floors into intelligent wireless sensing networks.

"The Chorus™ device is a dramatic example of a merger between Solidica's solid state ultrasonic consolidation fabrication technology and our industry-leading expertise in wireless electronics," said Dawn White, CEO of Solidica, Inc., in a statement announcing the award. "It's another example of the unique best of breed technology combinations that our customers have come to expect from us."

Solidica recently unveiled a version of the sensor that embeds a sub-millimeter integrated MEMS device directly between the 0.0006-inch fabrication layers of metal during the manufacturing process, enabling "truly in-situ health monitoring." A fully enclosed sensor, impervious to environmental conditions, is the result. While providing the latest technology in signal conditioning and wireless transmission capability, the sensor cannot be removed, tampered with, or easily destroyed.

"These sensors are so rugged that you could run one over with a truck, heat it to over 180 degrees Fahrenheit, immerse it in battery acid, and it will continue to report accurate data without breaking a sweat," said Rick Fortson, vice president of wireless technology, in the statement from Solidica.

Enhanced EMI Sensor Capability for Commercial HVAC/R Applications

The high levels of electrical noise generated by commercial HVAC/R systems have long restricted the use of electronic pressure sensors in these systems. But a new sensor from Sensata Technologies (Attleboro, Mass.) reportedly overcomes these dense electromagnetic interference (EMI) barriers, enabling HVAC/R system designers to integrate reliable and accurate pressure transducers into their system designs. The ceramic capacitive, hermetic sensor is available in a variety of pressure ports and electrical fittings.

According to Sensata, the 2CH case isolated pressure transducer provides EMI protection of 100v/m and a dielectric terminal-to-case strength of 1.8kVac. The device, offering pressure ranges between 100 and 750 psi and a burst pressure rating of up to 4X operating pressure, is suitable for "electrically challenging" environments, such as inverter driven compressors and advanced HVAC/R systems.

"The 2CH sensor can be used across a wide range of refrigerants and temperatures and it is priced to meet the industry's design-to-cost goals," said John Forsyth, Sensata's HVAC marketing manager, in a statement from the company. "System designers can now benefit from an electrically stable, hermetic sensor designed specifically for use in HVAC and refrigeration applications."

Virtual Instrumentation: A New Model for Building Measurement Systems

By combining the power of flexible software and commercial PC technology with a wide variety of measurement and control hardware, virtual instrumentation provides a new model for building measurement and automation systems while enabling accurate analog and digital measurements from DC to 2.7 GHz. Engineers and scientists that use virtual instrumentation, in which software based on user requirements defines the functionality of general-purpose measurement and control hardware, are able to create user-defined systems that meet their exact application needs. As a result, they can design higher-quality products while reducing development time and design costs, according to Austin, Tex.-based National Instruments (NI), a pioneer in the field of virtual instrumentation.

Better Products Without Redeveloping the Hardware

According to NI, virtual instrumentation is necessary to create the user-defined instruments that are required to keep up with the world's changing demands. It gives instrumentation the rapid adaptability required for the fast design, development, and delivery of today's concepts, products, and processes. Today, advanced electronics, processors, and software play huge roles in meeting the demands for innovation and faster product development of devices such as cell phones. And the higher functionality of today's devices is possible because they've become more software-centric, a defining feature that enables engineers to add new functions to a device without changing the hardware. Rather than developing new electronics to perform a specific function, engineers can use software to improve the functionality of a device, the company says.

Greater functionality, however, introduces another variable into the equation: the possibility of unforeseen interactions and errors. This, in turn, requires design and test instrumentation to adapt so that it can detect errors and verify improvements. According to NI, the only way to ensure this is to use test and control architectures that are also software-centric. Virtual instrumentation is able to keep pace with the demands for innovation and rapid development of new products by applying highly productive software, modular input/output (I/O), and commercial platforms.

National Instruments' LabVIEW software, which the company describes as "a virtual instrumentation graphical development environment," speeds up development through symbolic or graphical representations of functions. Development can be further speeded by consolidating functions within rapidly deployed graphical blocks, the company says. The second element of virtual instrumentation, modular I/O, is designed to be rapidly combined in any order or quantity to ensure that virtual instrumentation can monitor and control any aspect of development. Engineers can use well-defined software drivers for modular I/O to quickly access functions during concurrent operation. The third element, the use of commercial platforms, ensures that virtual instrumentation takes advantage of the latest computer capabilities and data transfer technologies.

Level, Temperature, and Proximity Sensors

High reliability, a must in sensor applications, is an area in which Madison Company (Branford, Conn.) strives to excel. The company designs and manufactures a variety of level switches and sensors, temperature sensors, and proximity sensors for OEMs in major industries worldwide, including food equipment, aircraft and marine, industrial equipment, specialty vehicles, and medical equipment. Its high-reliability sensors, offered in standard and custom-designed versions, are used in applications ranging from the Seawolf and Trident submarines to nuclear power plants, refrigeration systems, and coffee pots.

"Both catalog product and full engineered designs are available for level, temperature, and proximity measurement," says Ron Buchanan, executive vice president. "The technologies used are reed switch, conductivity, ultrasonic, radar, and optical for level and thermocouple, RTD, thermistor, and bi-metal switch for temperature."

One of the firm's biggest strengths, Buchanan says, is its ability to integrate a common user-programmable readout on its float switches, ultrasonic sensors, and resistance temperature detectors (RTDs). The Madison-Omni® integrated display/control unit gives systems a common, localized sensor control with user-friendly readout and alarms.

ISO-certified since 1997, Madison Company operates a 20,000-sq-ft facility where performance is consistently monitored by an internal quality assurance team to ensure conformance to customer requirements. The company utilizes Lean Manufacturing and Continuous Improvement techniques, complemented by inventory management options for reduced lead times and Just in Time delivery. To determine which manufacturing process is best suited to meeting a customer's requirements, Madison looks at the customer's demand pattern, product type, and supply chain considerations. The company typically works with plastics and stainless steel on projects for this industry.

As sensing technologies evolve, Madison seeks to develop new ways to apply its technologies as creative solutions to customers' problems. By incorporating temperature sensors into the level switch, Madison has achieved combination sensing that saves costs for customers. The company has also applied its knowledge of magnet and reed switches, used in liquid level sensing, to the use of proximity sensors for industrial equipment.

Madison Company recently added the U3M Ultrasonic Mini Probe to its range of ultrasonic level sensors. The U3M has a compact design that extends just over 2 inches in height above the tank or drum surface; its operating range is 4 inches to 6 feet (0.10m to 1.8m). The U3M's microprocessor-based circuits provide a temperature-compensated signal for improved accuracy and the ability to filter false echoes produced by peripheral obstructions, according to the company. On-board push buttons allow for calibration without the need for software and computers. Optional RS485 communications are available for computer interfacing and for networking up to 128 sensors.

The low-profile Mini Probe has a self-cleaning sensor face and is said to automatically adjust power and sensitivity to any environment. It can be used in a variety of liquids, including foods, beverages, chemicals, oils, and water, as well as slurries and some solids.

Continuous liquid level switches with an integral, compact alarm display are also available from the company. The Madison-Omni® sensors have an easy-to-read, graphical LCD and a separate red LED light that serves as a visual alarm when the programmed parameters are outside the preset ranges. The set of programmable options for the device includes level indication, unit of measure, and several other variables.

Capacitive Load Sensing Offers Cost, Design Advantages

A capacitive load measurement technique developed by Loadstar Sensors, Inc., Mountain View, Calif., is said to simplify and dramatically reduce the cost of load measurements. The company has developed a system to harness the advantage of capacitance-based devices, said to inherently offer "much higher sensitivities and resolutions than other measurement techniques." At the same time, the company says, its sensors aren't susceptible to shocks, temperature changes, and other environmental effects.

Loadstar's patented capacitive sensing technology was the basis of a new line of products that the company introduced last June, including the CS-Series of integrated load sensors, the DS-2100 four-channel display, and LoadVUE software. The new CS-Series load sensors, available in a compact, rugged stainless steel package, offer a large 0-5V measurable output without the need for external signal conditioning equipment. Their small size allows them to fit into tight spaces; they can also be mounted conveniently with threaded mounting holes on the top and bottom of the sensors. And because of their low power consumption (0.01mW), the sensors can be used with batteries.

According to Loadstar, its patented capacitive load sensing technology provides specific advantages over conventional resistive load cell technology. Because of the cost, size, and complexity of conventional strain-based resistive load cell solutions, it became difficult, if not impossible, to incorporate the functionality of load measurement into various industrial and consumer products.

"Our products, in contrast, can be used even with a 9V battery and DMM, and our 0-5V DC signal can be plugged directly into most common data acquisition and control systems, bringing the total cost down to about a third of what you would expect with conventional load cells," said Div Harish, co-founder and CEO of Loadstar Sensors, Inc., in a statement from the firm. "We can also make really thin but rugged load sensors in any shape, making it possible to incorporate our sensors easily into end products."

Loadstar's DS-2100 wired and wireless (DS-2100 WiFi) displays are designed to work seamlessly with the company's capacitive load sensors and LoadVUE software. The load indicators accept input from up to four CS-Series load sensors. They digitize analog signals using 21-bit analog-to-digital converters (ADCs) and they automatically sum loads from all connected sensors.

"The DS-2100 makes it easy to measure and display loads and output data directly to a personal computer's serial port," said Harish. "For users who prefer wireless connectivity, we offer the DS-2100 WiFi version that uses a virtual serial port to provide the same easy ASCII command set and data output format. Users do not need to struggle with data formatted in binary or hexadecimal systems to input data into common PLCs."

High-temperature pH Sensors Designed for Longer Life

A new generation of high-temperature sensors from Emerson Process Management is designed specifically for increased sensor life and greater performance in elevated temperature applications. The company's PERpH-X™ line of Rosemount® Analytical Models 3300HT and 3400HT high-temperature pH sensors are said to perform longer in temperatures up to 145ºC (293ºF).

According to the company, the Models 3300HT and 3400HT are the first releases of an entirely new sensor platform with a number of specialized design features. These include AccuGlass™ pH glass formulations, which reportedly resist cracking and maintain near theoretical response, even at extreme pH values and after exposure to very high-temperature applications. The sensors have an improved double junction reference, which can be refilled for extreme applications that may deplete reference electrolyte—a common problem in elevated temperature applications that can coat, foul, or produce large measurement offsets. They also feature a replaceable Teflon® reference junction to control electrolyte flow in dirty or oily applications, and a chemically resistant Ryton™ body contained in a titanium sensor tube for resistance to high temperature and pressures.

Dynamic Pressure Sensors for Turbine Engine Monitoring

Variations in natural gas can lead to increased dynamic pressure oscillations in turbine combustors, resulting in inefficiencies, increased emissions of NOx, and damaging combustion instabilities. To monitor these dynamic pressure oscillations in turbine engines, PCB Piezotronics, Inc. (PCB®), Depew, N.Y., has introduced its Series 171 dynamic pressure sensors. These sensors may also be used to detect high-intensity acoustics, pulsations, and pressure fluctuations in pumps, furnaces, and pipes, the company says.

According to PCB, piezoelectric pressure sensors are best suited for detecting and measuring dynamic pressure phenomena. These sensors provide very fast response times and can accurately measure fast transient pressures, such as surges, spikes, pulsations and noise. They have no moving parts, and their solid-state construction is said to provide excellent durability. The Series 171 pressure sensor has sensitivities to 1200 pC/psi (174 pC/kPa), pressure range of 10 psi (70 kPa), and a maximum pressure of 600 psi (4140 kPa). They are suited for high temperatures up to +500 ºF (+260 ºC) and are packaged in a case isolated housing with rugged, 2-pin MIL connectors.

Material from Business Wire and PR Newswire was included in this report.

For more on Oceana Sensor Technologies, Inc., visit www.oceanasensor.com.

For more on Sensicast Systems, visit www.sensicast.com.

For more on Solidica, Inc., visit www.solidica.com.

For more on Sensata Technologies, visit www.sensata.com.

For more on National Instruments, visit www.ni.com.

For more on Madison Company, visit www.madisonco.com.

For more on Loadstar Sensors, Inc., visit www.loadstarsensors.com.

For more on Emerson Process Management, visit www.emersonprocess.com.

For more on PCB Piezotronics, Inc., visit www.pcb.com.

For more on the IFTF, visit www.iftf.org.

ICHM® (Intelligent Component Health Monitor), SHM® (System Health Monitor), and Wireless e-Diagnostics® are registered trademarks of Oceana Sensor Technologies, Inc.

The Bluetooth® word mark is owned by the Bluetooth SIG, Inc., and any use of the mark by Oceana Sensor Technologies, Inc., is under license.

PCB and ICP are registered trademarks of PCB Group, Inc.

Sensicast and Sensinet are registered trademarks of Sensicast Systems, Inc.

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