Europe's Biggest Measurement Fair - in Early June in Nürnberg

Sensor+Test: The 21st international SENSOR+TEST trade fair will be held from the 3rd to the 5th of June 2013 at the Nürnberg Exhibition Center. The SENSOR+TEST is a must-go venue for developers, engineers, and users from all industries as well as for engineering and science students. State-of-the-art sensor and measuring technology is crucial for the sustainability of devices, machines, systems, and processes. Moreover, without the latest testing technology, the ever-increasing demands on the reliability of products and processes could not be met.

There is no comparable platform in Europe where innovative users can meet so many innovative suppliers of sensor, measuring, and testing technology from all over the globe. The AMA Association for Sensors and Measurement backer and AMA Service organizer count with about 550 exhibitors and approximately 8,000 visitors.

Focal Topic for 2014: Safety & Security
Today’s sensors and measurement technology are providing more and more safety and security in all areas from everyday life to industrial processes. Low-maintenance sensors reliably detect toxic and inflammable gases to ensure air quality, they control air-conditioning systems, and other sensors are integrated in wind-park condition monitoring systems, triggering alarms per SMS, while fiber-optic sensors check for fatigue in aircraft components. The range of safety-relevant applications is extremely broad.

This is why the Exhibitor Committee and the Executive Board of the AMA Association opted for “Safety & Security” as the focal topic for the SENSOR+TEST 2014. Visitors can obtain a specific and concentrated overview of products and solutions dealing with safety and security at the special forum in Hall 12. The lecture forum in Hall 12 will also be devoted to the subject of safety and security on 3 June 2014 and offers a subsequent podium discussion.

Product Overview of the SENSOR+TEST 2014

The text below is based on the preliminary information given by the exhibitors to AMA Service, the fair organizers, up to early February 2014. It comprises a preview of products, services, and trends that can be seen and experienced at this year’s SENSOR+TEST from 3 to 5 June 2014. The structure follows the trade fair’s nomenclature.

Geometric Parameters
Determining distance, gap, position, angle, tilt, and attitude – or fill level for that matter – are among the most common measurement tasks. Thus at the SENSOR+TEST, diverse sensors for such geometrical parameters measurements can be found. They are used in smartphones, brake test benches, driver assistance systems, robots, or a plethora of other special tasks.

For position tracking of individuals in buildings, shoes are shown with integrated inertial sensors. They are to enable navigation without external references, such as radio, GPS, or mapping tools. The development aims to include locating and tracking emergency or rescue teams.

Applications that require an exact waypoint bearing or precise orientation data, may be able to use a novel sensor principle based on the earth’s magnetic field. Such sensors, made in Great Britain, provide magnetic field measurement of <10 nT, or approximately 0.1% of the magnetic field, as well as SPI and an I2C interface. The newly developed ASIC not only offers the usual amplification adjustments, but also excellent noise-suppression characteristics.

For magnetic sensors, associated with angle, distance, or position measurement, compact SMD sensor packages are now presented in LAG6 size. An LAGmulti is available for integration of signal processing. The supplier is also showing a number of extremely precise material measures. Magnetization is based on a pulsed process with various materials and provides the foundation for reliable results with linear scales and pole rings.

A very flat rotary encoder has been developed for motor speed detection and determination of the exact angular position of electromotors. These work with reflecting code wheels, allowing the light source and light receiver to be in the same plane. The exactitude enables a 4-fold interpolation with an angular tolerance of less than ±0.14°. The encoder is available as a modular kit for easy integration in motors.

A newly developed product series with scalable measuring characteristics is to facilitate a start in radar-based measurement. The devices are able detect moving objects at a distance of 0.3 to 80 m and velocities between from 0.2 to 250 km/h. A robust IP67 housing provides a wide range of applications in different environments. Working with ultrasound instead of radar, a sensor for parking assist systems will be presented in Nürnberg by an enterprise from South China. This supplier also offers a selection of fill-level sensors, which measure the speed of an ultrasound signal – of water in a container for instance. A number of pressure transducers for level measurement also come from China. Enclosed in a stainless-steel housing, they can be used to measure levels from 1-m to 200-m depths. Explosion-proof versions are available for application in hazardous environments, such as in mining. A fluid level switch is now available as a mass-market product for OEM integration. It is based on an infrared principle, in which a point-level sensor detects the presence or absence of most liquid types.

The entire spectrum of state-of-the-art quasi-conventional sensors for geometric parameters can of course also be found at the SENSOR+TEST. One example would be an inductive position sensor with displacements of up to 15 mm, highly integrated, with a diameter of only 10 mm, a linearized output signal of 0 to 4 VDC, and encapsulated as per protection class IP68. It is designed for use in oil mists, rain, sludges, or dust. Long-life linear position sensors for stroke lengths from 25 mm to 290 mm are to be presented. Made for use in motorsports, they operate at 10 m/s, at temperatures of -40 to +150 °C with a short-term limit of 175 °C, and are shock resistant up 50 g. With a dual-seal design, an IP67 rating was obtained. Also designed for rugged ambient conditions are inductive proximity switches in a full-metal housing. Rapid changes in temperature, as occur in the steel industry, extreme vibrations, aggressive cooling agents, or hot sharp-edged metal shavings will not impair the sensor’s functions, says the supplier. Sized from M8 to M30, sensing distances up to 40mm are realized. The supplier also has a product line now that supports the I/O-Link automation interface. This allows a query of the switching status, temperature, and other operating states.

Mechanical Parameters
This section summarizes the initial exhibitor reports dealing with such parameters as pressure, differential pressure, force, weight, torque, or density. You can expect a wide range of standard transducers at the SENSOR+TEST, but this is also the very place to find specialized and exceptional devices. 

Take an absolute pressure sensor, for instance, with a 24-bit resolution and a measuring range from 10 to 2,000 mbar. At 0.02 mbar you can detect an altitude difference of 16 cm. Add an integrated temperature sensor with a resolution of 0.02 °C and you get a component designed for extremely precise altimeters or variometers for use in multifunction watches or mobile, battery-powered barometer systems that need a processor anyhow. That is why the sensor can also be equipped with its own processor with an SPI and I2C interface for further data processing. The sensor’s manufacturer is also presenting special low-pressure sensors with a measuring range of 10 to 100 mbar, both as a differential and bidirectional-differential design. These are made for use in respirators, negative pressure wound therapy, or sleep-apnea monitoring.

Also operating in the low-pressure range are sensors for monitoring clean rooms or hygiene plant zones. This is about production areas for semiconductor components or pharmaceutical products, where preventing contamination is crucial. Appropriate pressure measuring equipment connected to these hygiene zones, is usually located in control cabinets, where output signals that control ventilation are emitted.

Reports from versatile Chinese suppliers – always well represented at the SENSOR+TEST – mention the further development of their process transmitters. Many of these offer standard analog signals with an RS485 interface or parameterization as per HART protocol. The sensing technologies involved include silicon-based piezoresistive thinfilm strain guages, with an integrated temperature sensor if desired. Many of these devices are scalable and equipped with limit switches (relays) and fault-diagnosis functions. Also mentioned in this context are Ex-protection standards and UL certifications. Typical areas of application are petrochemicals, oil drilling, metallurgy, steam, water and wastewater, or natural gas. The transmitters are also used for flow metering (pressure drop) in these areas.

Very compact transmitters for wet/wet differential pressure measurements, such as for contaminated water, solvents, or aggressive gases, are to be found in Nürnberg. They are designed for application in the food industry or in chemical/pharmaceutical production processes, where they monitor filters, fill levels, or flow. Pressure transmitters with wireless transmission of measured values are designed for mobile or rotating systems. This concept is also eminently suited for temporary measuring points or centralized data acquisition of distant measurement sites.

Needless to say, the entire spectrum of standard pressure transducers is also well represented at the SENSOR+TEST. They range from completely encapsulated models with sputtered thinfilm strain gauges and exceptional impact and vibration resistance to the more common pressure transmitters with silicon sensors in oil-filled capsules and standard output signals, for absolute, relative, or differential pressure. A complete pressure transducer with a voltage output for measuring ranges from 2 to 250 bar is to be shown. It has an M8 threaded connector, 14-mm diameter, and 32-mm length. The thin-film strain gauges permit temperatures of -40 to +125 °C and provide a long-term stability of ±0,1 %.

Last, not least, we have the pure sensor element and system offerings at the fair. Examples: stainless steel capsules with thin-film strain gauges, weld-on capsules with a piezoresistive oil-filled sensor with a diameter of only 12.6 mm or encased pressure sensors produced in MEMS technology as components for machine-assembled PCBs to be used in washing machines, refrigerators, or air-conditioners. Capacitive ceramic pressure sensors are now being equipped with a novel ASIC that provides not only analog interfaces, but also two separate digital interfaces (SPI / UART). Measuring ranges from 50 mbar to 70 bar are realized with diameters of 32.4 and 17.5 mm.

Force, Weight
A force transducer of the more complex kind measures shearing parameters of workpieces in machining equipment and wirelessly transmits the measurements to a data-acquisition and evaluation unit. This considerably increases the optimization potential. Probably just as complex is the measurement by a 6-axis sensor of forces and moments applied to golf club as a training aid for golfers. These are just two examples of the plethora of force sensors at the SENSOR+TEST – including some quite exotic, but exciting exponents.

Close thematic relatives of these force transducers are weigh and load cells. A broad range of offers in standard and special measuring cells can also be found in Nürnberg. A low-profile shear beam load cell of only 19.1 cm height for a rated load of 500 kg would likely fall in the latter category.

Torque
Just a few years ago, contactless measuring of torque on a static or rotating shaft would have been hard to imagine. Today we do just that at a distance of 2 mm to the magnetizable shaft turning at up to 10,000 rpm and get the measured results in realtime. One enterprise has enhanced its torque measuring flanges by adding EtherCAT to its selection of network connections. This enables fiber-optic cabling to transmit up to 6,700 measured values per second over large distances. The rotating torque sensors of another enterprise operate at a sampling rate of up to 2,500 measured values per second, albeit with a reduced power consumption at the USB level. This lets you use a PC or laptop as a display and evaluation unit for the scaled measuring values. 

Density
A simple means of determining the density of a liquid is by using a hydrometer. Floating hydrometers made of unbreakable plastic can be found for various measuring ranges at the SENSOR+TEST. With optional, DAkkS-certified, in-house calibration, reliable measurements are available for quality-assurance systems, e.g. in the food industry

Dynamic Parameters
The advent of MEMS technologies has made mass production of vibration and acceleration sensors viable, along with gyroscopes for detecting rate of rotation and position. Some such, labeled as “next generation,” are presented at the SENSOR+TEST. The wide spectrum of sensors for flow, rotation, speed, etc. may surprise the visitor. 

Take a sensor for mass-flow measurement in gases with a high degree of humidity or water vapor. The thermal measuring process, patented in the U.S.A., is used in medical technology, semiconductor production, or analytical applications. This exhibitor will also present a handheld device with integrated data storage for mass-flow gas metering, used for gas chromatographs, air sampling, or leak detection. Sterilizable and biocompatible is a Swiss flowmeter with a measuring range of 0 to 120 ml/min, especially designed for applications in medical technology and diagnostics. It works very precisely, measuring microthermally through the flow channel’s capillary wall and has no moving parts or obstacles to the flow. Its measuring rate is 1 ms.

Designed to target suppliers of water and heat flow meters, is a system-on-chip development. With only a external components, the chip offers a measuring rate of 8 Hz at a power consumption of only 7 µA. The concept clearly distinguishes between the measuring task itself, device management, and external (wireless) communication. Signal processing is carried out in a 32-bit processor, providing a calibratable, digital output signal at an SPI.

Thanks to the development of a special IC, a Japanese company was able to reduce the size of its previous design down to 10 x 12 x 4 mm and a weight of approximately 1 g. This “world’s smallest inertial measurement unit (IMU) in its class” is to be presented at the SENSOR+TEST. It boasts a gyro bias instability of less than 7 °/h. Also available from this company are further IMUs providing measuring rates of 2 kS/s. These have inputs for external trigger signals and a reset function for the internal counters to enable better synchronization with GPS modules, for instance.

Coming from China, we have triaxial vibration sensors, developed for acceleration applications in vehicular or aerospace projects. The measuring ranges extend from ±2 g to ±1000 g. The gas-dampened sensors are able to detect slow vibration frequencies and long impact pulses. Designed in capacitive 3D-MEMS technology is a sensor system that meets the international Automotive Electronics Council (AEC) standard Q100 and provides multiple options for self-diagnosis. The sensors for all three spatial axes are shock-resistant up to 20,000 g and the temperature range can be optionally upped to +125 °C. Typical applications include vehicle suspension and electronic stability control (ESC). Triaxial measuring is not solely a domain of mobility – it is also of significance in real estate. Such vibration monitors are also used to monitor buildings, bridges, towers, or pipelines. The device presented in Nürnberg can perform this task autonomously, while storing event-driven data. In case of emergencies, e.g. when preset limits have been exceeded, an SMS is sent.

Applications at temperatures of up to 650 °C are accessible to piezoelectric vibration sensors. Such hermetically sealed sensors, with bandwidths of 5 or 10 kHz, are used on turbines, vehicle engines, or in the exhaust tract. Suitable stainless-steel cables with fiber-optic sheathing are available.

A speed sensor can be made by combining a GPS sensor with an inertia sensor. The down side of either technology is surmounted by a CAN interface for passing accurate data for acceleration, speed, or length during brake tests, for instance. For non-contact speed (or length) measurement in an industrial environment, optical sensors are to be shown by a Belgian enterprise. The sensors overcome the disadvantages of contact encoder wheels.

Thermal Parameters
The market for temperature sensors and measuring devices seems endless in regard to size and variety. This impression is imparted by the SENSOR+TEST every year. Besides standard sensor elements, such as NTC, Pt100/Pt100 or the numerous types of thermoelements, non-contact temperature measurement is strongly represented. For experts, the probability of finding the right solution even for very special applications is thus is extremely high. 

To obtain the price level for white goods or HVAC applications, platinum-chip temperature sensors are being offered now with metallic blank nickel wires. Such wire can be easily processed without reducing the quality of the measuring results and is clearly much cheaper than platinum. Targeting the HVAC sector as well is a high-precision chip sensor. We are talking about a complete IC with an integrated 24-bit ADC. This sensor has an SPI and an I2C interface, does not take up much space thanks to its QFN package, and is eminently suited for mobile or battery-operated devices due to its low power consumption (sleep mode). A special kind of non-contact temperature sensor originates in France. It makes use of surface acoustic waves (SAW) technology and achieves an exactitude of up to ±0,5 °C in a range of -15 to +165 °C. The size of the passive chip is 5 x 5 mm and does not require a power supply of its own. The distance to the interrogation system can be up 5 m. The applications are mostly in process technology, but also for tasks in involving smart grids for electric power supplies, where insulation clearance is an important factor. The manufacturer will also present a novel interrogation module that can process up to 6 measuring points. A sensor with radio-frequency identification (RFID) technology and thus non-contact interrogation has a diameter of only 15 mm. Technical product data and calibration data are stored internally to enable identification during queries.

Temperature Measurement Devices
Anyone interested in the state of the art in infrared pyrometers and cameras would do well to visit the SENSOR+TEST from 3 to 5 June 2014. This is where digital infrared pyrometers for measuring dynamic processes or short temperature peaks are to be found. A response time of 0.5 ms in a range of 50 to 1,800 °C increases process reliability, especially for induction hardening, welding, soldering, annealing, forging, and sintering or in manufacturing processes for ceramics, graphite, and other carbon-based materials. The optics can be manually focused and parameterization and signal processing can be delegated to the included software. The supplier will also present a UV pyrometer for a measuring range of 650 to 1,300 °C, set to a spectral wavelength of 400 nm. This is particularly useful for measuring wafer temperature during the production of LEDs for displays. Complemented by a laser reflectometer, the thickness and growth rate of GaN layers can be observed during epitaxy. Handheld pyrometers and quotient pyrometers are also in the product range. 

A thermal imaging camera with the largest commercially available, uncooled microbolometer-detector (native resolution of 1024x768 pixels) is to be shown for the first time at the SENSOR+TEST. The capability according to NATO standards is 6.1 km for identification of persons and 10.1 km for vehicles. The integrated telephoto lenses offer an exceptional aperture ratio, uses a high-performance coating, and is exactly calculated for the detector resolution of 17 µm. For users in industry and research, this supplier also offers a high-speed thermography camera. The detector has a resolution of 640 x 512 IR pixels, a sampling rate of 350 Hz at full resolution – 1,000 Hz can be attained in the quarter-frame mode. The thermal resolution is 25 mK. An integrated trigger interface and other digital I/O ports are for synchronization with fast, repetitive sequences. Features, such as changeable optics, spectral filters, motorized focusing, etc., are available. Thermography can also be used to reliably monitor parts made by injection molding. A camera to be shown at the SENSOR+TEST allows the observation of up to eight areas of the part’s surface. Each measuring point has individually set fault tolerances and every measured result can be allocated to a specific part. The camera can control a scrap gate through a control signal. However, its application is designed to improve the entire production process.

Measurements on high-voltage assemblies are dangerous and require compliance with safety regulations. This entails the use of safe, certified measuring devices. A measuring transducer for thermo-element sensor probes of type K has absolved the required tests and received the proper certification. Each of its inputs is protected by a voltage divider for up to 800 V. With protection class IP67 and an operating temperature range from -40 to +100 °C, the device can usually be operated in the vicinity of an HV battery in hybrid vehicles. The included thermo-cable is certified as well.

Temperature Probes
One exhibiting enterprise supports its customers from prototype to series production. About 600 temperature sensor elements can be selected, the stress being on Pt, NTC, or KTY types. Customized designs for medical technology, racing, energy technology, or measuring and control technology in general, all of it is on sale. And that includes the attachment of special extensions, such as a cross-section of 0.02 mm², PTFE insulation for temperatures of up to 200 °C, or lately the customization of Peltier elements. 

A fiber optic thermometer for the range of -200 to +300 °C is characterized by an exceptionally low sensitivity to electromagnetic radiation up to the microwave range. A number of interfaces as well as analog and relay outputs enable diverse applications in the lab and industrial environments.

A series of temperature probes, especially designed for food-industry production and monitoring is to be on display at the SENSOR+TEST. Probes for cooking and baking are manufactured under hygienic aspects in regard to material, form, and cable. They use a number of different sensors. Similar designs have been developed for applications in sterilizers. Screw-in probe or bolt-on probe? The former is a temperature probe with a measuring rod, held in position by a threaded stud. The latter is usually a hex bolt, in which a temperature sensor is inserted and encapsulated. The temperature-measuring applications differ accordingly: either in ducts, pipes, and conduits; or on the surfaces of plant and machine equipment.

Last, not least, an offer for all involved with thermoelements: To cut costs for special metal wires on thermoelements, extension and compensation cables can be used. They are not supposed to distort the measuring results, nor have particularly narrow tolerances. Suppliers of this kind of equipment can be met at the SENSOR+TEST.

Climatic Parameters
This section is mainly about a combination of humidity and temperature measurements. There are also plenty of sensors for barometric air pressure, atmospheric gas concentrations, smoke, dust, or solar radiation, for that matter, all of which can be found at the SENSOR+TEST. 

A combination of capacitive humidity sensor, temperature sensor, and suited ASIC was integrated in a 3-by-3-mm DFN chip housing with a height of 0.9 mm to arrive at applications with a large number of units. Each of the sensors is individually calibrated. The response times are within a few seconds, even after reaching the dew point. With its I2C interface it can easily be integrated into higher-level systems. Especially designed for the completely new market for wearable electronics, smartphones, and other consumer products, a chip is presented in Nürnberg for temperature and humidity measurement with the exceptional dimensions of 1.3 x 0.7 x 0.5 mm. At a sampling rate of 1 Hz, the power consumption is 2 µW. The measuring ranges are specified to go from 0 to 100% RH and -30 to +100 °C. The integration in higher-level systems can be accomplished via an I2C interface.

For application in autoclaves, dryer systems, or other such processes, a humidity/temperature module is to be presented in Nürnberg, that is condensation resistant and can withstand an ambient pressure of up to 16 bar. Tolerances of ±1,8% RH are reached. The modules are provided in customized housings. The supplier is also presenting a humidity and temperature measuring module for building automation and the interiors. In a wall-mount housing are a capacitive polymer sensor and a Pt resistor as well as a signal-processing ASIC for the standard output signals at 0 to 10 V. Designed for the HVAC equipment and climatic chambers is an Italian humidity/temperature module. It has the usual analog process signals as well as an RS485 interface for bus systems.

A rain detector for automatic control of roof windows or awnings is shown at the SENSOR+TEST. Its adjustable sensitivity can also be set for fog or snow detection. The major fields of application are in building automation and nurseries. Also made for building management is an air meter for tracking ventilation costs. Like a water or electricity meters, the device is to ensure a just distribution of ventilation costs, e.g. for shopping-mall tenants. Dust is raised occasionally and easy to detect. The same cannot be said about fine-dust measurement in real-time or for long-term monitoring of concentrations of up to 300 mg/m³. A portable device for doing exactly that using light scatter technology is presented in Nürnberg as well.

Optical Sensors / Sonic Measuring Systems
There are more than enough fields of application for optical sensors: gas and particle measurement, fluorescence and analysis techniques, spectroscopy, temperature measurement, motion detectors, high-resolution positioning systems, etc. Among the major characteristics besides sensitivity relative to wavelength is always the signal-to-noise ratio. Not only sensors are used in these applications, but special light sources – often laser diodes – as well. 

Panchromatic photo-sensors with InGaAs detectors offer a sensitivity range of 450 to 2,000 nm. They are integrated in a housing with an M12 thread and can be networked. They also have a measure-on-demand function, internal memory, a digital and analog output. The data can be tagged with a time stamp as evidence. Monitoring the color temperature of an object, for instance, was realized by two silicon PIN photodiodes integrated in a TO-5 housing. Their bandwidths add up to 300 to 1100 nm and the ratio of the two photo streams can be evaluated. Whenever we need to consider an increased sensitivity in the UV spectrum, SiC is the material of choice for photo-detectors. These are then used for high-resolution position measurements. The active surface area of the new models is 1.6 mm², the wavelength having the highest sensitivity is 270 nm.

A supplier from Saxony is showing highly sensitive IR sensor arrays for applications in spectroscopy and gas measuring technology in Nürnberg. Sensors with radiation-sensitive surfaces of 3 x 3 mm² and 8 x 8 mm² are being presented, for example. A thermally compensated 2-channel sensor for the spectral range above 1.3 µm is also available. New at the fair are linear sensor arrays with 128 to 510 pixels for compact spectroscopic measuring systems including a test board with a USB port.

Not just spectral sensitivity, but surfaces on organic photodiodes can be customized. They can be integrated on flexible polymer films or combined into arrays. Moreover, today it is possible to also place OLED light sources on the same component. These organic photodiodes are shown in Nürnberg for the first time.

A multi-channel pulse scaler for applications, such as a photon counting, is presented by a British exhibitor at the SENSOR+TEST. The modul has a trigger input and a USB port. Data retrieval is controlled by the supplied software.

Compared to conventional laser diodes, vertical cavity surface emitting lasers (VCSELs) have the advantage of consuming considerably less power at the same light output and providing excellent temperature stability. A new VCSEL attains an efficiency of 0.4 W/A at 850 nm and a CW output of up to 20 mW. The supplier also presents a worldwide novelty in Nürnberg: a laser diode for 785 nm, optimized with VBG technology and an internal temperature control. The wavelength has a bandwidth of only 0.1 nm at an optical output of 120 mW. Fields of application include Raman spectroscopy and medical technology. Also designed for spectroscopic applications are distributed feedback (DFB) lasers with high output power. They are partially equipped with integrated Peltier cooling elements for wavelengths from 1278 to 1650 nm. Also to be seen is a new generation of pulsable infrared emitters with a considerable yield above 4.5 µm.

For liquid phase spectroscopy or spectroscopic analysis at the tip of atomic-force microscopes are quantum cascade lasers that can be used as tunable light sources in a range of 3.2 to 12.5 µm.

Sonic Measurement
Thanks to the big topics dealing with measuring and testing technology – especially in the area of vehicle development – visitors to the SENSOR+TEST can obtain information on the state of development of measuring microphones and acoustic measuring technology in general. Suppliers of acoustic cameras, for instance, who present their improvements and expansions in the area of evaluation software. One such platform does not only provide localization of sound sources, but also far-field measurements and evaluations of sound power levels. 

Chemical Sensors
Sensors for determining the concentration of combustible (explosive), toxic, or other gases, have been at the focus of the SENSOR+TEST for years along with their various technologies. In the reports submitted by the exhibitors this year, optical processes are emphasized. Alongside catalytical sensors, there is a wide offering of wet chemical sensors for determining parameters, such as pH value, oxygen concentration, or conductivity. 

A laboratory device is designed for odor evaluation of products by random sampling. It has a high rate of reproducibility, which according to the supplier clearly sets it apart from conventional artificial noses. Its software records complex signal patterns from the sensors and classifies the examined products on the basis of a statistic process in reference to trained values. The major users are the cosmetic, food, packaging, plastic, and pharmaceutical industries.

By means of selective IR filters, thermopiles, which actually detect temperature changes, can be used as single-channel detectors for analytics, while dual-channel thermopiles are used in non-dispersive infrared (NDIR) gas measuring. As a sensor system they usually have an I2C interface and an evaluation board with a USB port. The sensitivity of conventional thermopiles can be improved by dividing the irradiated surfaces into pixels and adding up the respective voltages. The output signal of these low-noise pyroelectric detectors is ten times greater than the usual value. Up to four detectors can be placed in a TO39 housing. New detectors with tunable Fabry-Pérot (FP) filters are equipped with an ASIC for integrated control to compensate low-frequency vibrations, gravitation effects due to turning portable devices, and temperature drift. This allows the stabilization of the wavelength down to ±2 nm. The expanded filter tuning range now allows the detection of the CO2 absorption band.

Portable multi-detectors for highly inflammable gases operate with new sensor systems in NDIR technology, have an extremely low energy consumption of 3.5 mW, while maintaining a 10-s response time. The devices have an intrinsically safe design and are equipped with a microprocessor, which allows customization of characteristics. For applications in vehicles running on natural gas, searching for leaks on pipelines, or in portable devices, a Japanese methane sensor in MEMS technology is presented in Nürnberg. According to the supplier, it presently has the lowest energy consumption compared with other sensors on the market. A single lithium battery (2.8 V/2400 mAh) is expected to have a service life of 5 years. This supplier also makes catalytical sensors for liquid or natural gas in vehicles or domiciles. They are distinguished by their high degree of reliability. As opposed to the aging process of conventional sensors, the sensitivity of these sensors increases in the long term. Cross-sensitivity was reduced and the resilience to corrosive gases increased.

Based on infrared absorption (NDIR), a module is available for CO, CO2, SF6, methane, n-butane, and propane. It can be optimized for a variety of refrigerants used in refrigeration-system applications.

The same measuring principle is applied in industrial gas analyzers, capable of measuring concentrations of six or eight gases simultaneously. They are set up according to customer specifications and are equipped with interfaces for process control. A new generation of NDIR gas sensors comes from Italy and has an integrated microprocessor for measuring concentrations of hydrocarbons, carbon-dioxide, refrigerants, or SF6 gases. The amperometric sensor from a Japanese manufacturer monitors the ammonia concentrations inside of refrigeration systems at temperatures down to -30 °C, regardless of the ambient temperature and humidity.

Another Japanese exhibitor is showing electrochemical sensors that can measure concentrations of hydrogen in inert gases, such as nitrogen, without being impaired by silicon or sulphur compounds and without the need for oxygen.

A carbon-monoxide sensor makes use of the fuel-cell principle. It can be used for monitoring buildings, detecting smoke, controlling ventilation in car parks, or monitoring campers and RVs. Its typical life cycle is seven years. For monitoring on-load tap-changers or transformers, gas sensors with NDIR technology suited for gas-in-oil analysis are being presented at the SENSOR+TEST. Based on a dissolved-gas analysis (DGA), the supplier offers condition monitoring of energy generation, transmission, and distribution systems, including temperature monitoring of transformers. Another monitoring system from this supplier can evaluate air samples taken serially at up to 24 locations. The sensors are boasted on the photo-acoustic principle and available for the most diverse gases. Typical applications include monitoring of enclosed spaces for concentrations of toxic gases, ethanol concentrations from tailpipe emissions, monitoring of gases released in chemical processes, etc. Sensitivities down to the ppb range can be attained with additional optical filters.

Visitors to the SENSOR+TEST will find a wide range of offerings for determining oxygen concentrations. A galvanic measuring cell has practically no cross-sensitivity to carbon-dioxide and a good linearity of about 30%. Typical applications are in biochemistry, the food industry, and numerous monitoring tasks. A particularly good long-term stability distinguishes a measuring cell that uses an acidic electrolyte. Cross-sensitivity to CO2 or other acidic gases were not observed. Another oxygen sensor is based on fluorescence. It requires very little energy and can be used in a temperature range of -20 to +50 °C. A zirconium-oxide sensor is used to measure oxygen concentrations from 50 ppm to 95% at temperatures of up to 300 °C. The applications extend from monitoring of combustion processes, gas analysis, food storage, incubators, respirators, etc. Another model of this kind was specially designed for monitoring and optimizing combustion processes. Besides the sensor for determining oxygen concentrations in gases, the visitors to the SENSOR+TEST in Nürnberg will also see sensors for dissolved oxygen. By means of an optical process, particularly long-term stable, low-maintenance sensors are applied in potable water monitoring, water pollution protection, or fish farming.

Air Quality
Another focal area in gas sensors this year is the subject of air quality. A low-cost complete system detects CO2 concentrations – and optionally oxygen concentrations. The display is based on the traffic-light principle and has adjustable levels. An air-quality sensor with diverse functions and a low power consumption is used to improve the energy efficiency of systems for providing buildings with air. A hygrometer also in the area of HVAC with an infrared-optical CO2 sensor was enhanced with a patented autocalibration process that promises high precision over many years.

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