Sensors in industrial automation: A look at technology trends

Sensors are part of an exploding market, and developments are occurring at a phenomenal rate. The technology is indispensable to a broad range of industries, providing critical information about such parameters as pressure, temperature, flow, gas and position, which can have a profound impact on a number of processes or systems.

The proliferation of advanced electronic control systems has provided sensor users ongoing advances in sensor accuracy, reliability, response time, robustness, miniaturization, communications capability and efficiencies. This has fueled research and development in the sensors industry, which in turn creates opportunities for technology advancements that open up new applications for sensors.

Application support holds the key to the development of new technologies. For instance, a liquid level sensor may be applied in industrial sectors ranging from chemical, paper and pulp, petroleum to food and beverage. Specific applications in these industries may include the use of sensors in cooling towers, fermentation vessels, fuel storage containers, blending and solvent level monitoring vessels, to name a few.

What drives the adoption of the core technology in the industrial sector is the availability of a solution that can provide seamless integration into existing automation systems. There exists a need for technology and product development to be focused on industrial applications through appropriate additional integration and value-added test. This must, in turn, be supported by a long-term strategy and roadmap for the industrial market.

Technology trends
The mantra adopted by the sensors industry in general is smaller, faster and cheaper solutions. Sensors that are important in the current industrial scenario include temperature, pressure, force and load, level, micro-electro-mechanical systems and nanotechnology. For example, new research from Rice University’s Laboratory for Nanophotonics suggests that nanosized gold particles called nanostars could become powerful chemical sensors.

Sensor manufacturers have significantly improved measurement technology, although the different types of industrial measurements have not changed much. Today, sensors offer a number of capabilities, such as increased sensitivity, faster response, decreased hysteresis, and longer-term stability and durability. Further, there are now sensors that can offer multiple types of measurements such as U.K.-based Sensornet’s DTSS, which measures dynamic distributed strain, and independent temperature and strain in the same fibre.

The ability to introduce the “smart” factor into sensors will continue to drive their application in industrial and process control applications. The industrial sector stands to gain from the design of low-power microsensors, embedded processors and radios that monitor a broad range of parameters on a factory floor to maintain production. Also, the introduction of smart sensing and calibration solutions that enable a variety of sensors to have plug-and-play capabilities across many applications helps to streamline the manufacturing and assembly of smart sensors and sensor-based products and systems. Further, the analytical capabilities of smart sensors can be installed on-board by using miniature microprocessors; attached close by using wires; or remotely through wireless networks.

Industrial automation presents numerous opportunities for wireless sensor networks. This may be in areas where the sensors are expected to be flexible, have high expendability rates, and where cabling is very expensive. High-capacity wireless sensor networking is still an emerging technology, and the current view on wireless technology for the industrial automation and process control market is that this technology can provide a means to augment legacy sensing systems that would provide a next level of information for intelligent control and automation. However, the early implementations of wireless will be around sensing applications versus control. The biggest opportunity for wireless sensor networks in the industrial sector lies in sensing devices in remote or inaccessible areas, including nuclear plants, oil and gas fields, and high temperature furnaces. Wireless protocols facilitate installation of the sensors in inherently hostile industrial environments.

The implementation of wireless sensing devices may commence with the development of an entirely new class of sensor that requires firmware processes for both the network stack and the sensor application to operate in a single monolithic environment, operating on a single processor. This poses numerous challenges, including complexity of design and difficulties in bringing the products to market. Addressing this is Sensicast Systems Inc. The Needham, Mass.-based company’s MIND platform is designed to allow third parties to rapidly develop wireless devices based on wireless sensor networks that system integrators and independent software vendors can deploy in end-to-end solutions at customer sites. It offers a way to develop wireless sensors for mesh networks.

Wireless sensor networking is a reality today, and innovation in this area will further increase its potential. Improvements down the pipeline include smaller components, faster data-exchange rates, longer ranges and better battery life. Also, batteryless sensor nodes that run with energy from vibrating machine parts, temperature differential, electromagnetic waves such as light, radio waves and infrared waves compete with battery-powered radio solutions.

Previously, the main concern that existed with wireless sensors was whether there was sufficient smart energy to power it. Rapid progress of smart energy technologies has resulted in the concern shifting from whether the smart energy solutions are possible to the cost involved in adopting these solutions. Energy autonomous solutions for high-volume industrial sensors compete with battery-powered radio solutions. When energy conversion costs become comparable to battery costs – at similar performances of the system – the advantages of maintenance-free energy autonomous solutions will definitely ensure broader acceptance. Energy sources such as moving objects, vibrating machine parts, temperature differential and electromagnetic waves could be harnessed to power small, wireless and maintenance-free radio switches and sensors.

Conclusion
Market factors that influence sensor technology and product-related developments include cost, competitive differentiation, resistance to change, standards evolution, and government regulations. Over the past year, a number of developments both in the academic and corporate sector have facilitated low-cost sensor solutions. For instance, last year Waterloo, Ont.-based Dalsa introduced the FT50M image sensor that offers sensor-based control of industrial processes at decreased production costs. This sensor has been designed to meet the demanding needs of the industrial market specifically in industrial inspection.

Reduced operating costs, enhanced performance, and a high return on investment drive technology development – especially in industries such as oil and gas. Austin, Texas-based SensorTran Inc. launched the SensorTran 1500 DTS to make use of the benefits offered by distributed temperature sensing to track actual infrastructure conditions through temperature monitoring.

Based on recent technology developments, technological and price barriers will disappear over the next few years, creating new applications for sensors in a wide range of industrial sectors.

Archana Jayarajah is a technical insights analyst for Frost & Sullivan.