The 20th international trade fair for sensor, measuring, and testing technology, the SENSOR+TEST, will be held from 14 to 16 May 2013 at the Nürnberg Exhibition Center. The SENSOR+TEST is a must-go venue for developers and engineers from all industries as well as for technically oriented engineering and science students. Without today’s sensor and measuring technology, appliances, machines, systems, and industrial processes could not be designed according to the state of the art or further developed in view of future innovations. Moreover, without the latest testing technology, the ever-increasing standards of quality could not be met within the cost limits imposed by external factors. There is no comparable platform in Europe where innovative users can meet so many important suppliers of sensor, measuring, and testing technology from all over the globe.
The AMA Association for Sensor Technology and AMA Service organizers count with 550 exhibitors and approximately 8,000 visitors
Focal Topic 2013: Renewable Energy
The increasing generation of energy from renewable sources comes with a plethora of new requirements for the needed sensor, measuring, and testing technology. Take wind farms on the high seas, solar power plants in the desert, or biogas plants in the neighborhood: more and more facilities are distributed over an ever larger area. In the future, the importance of intelligent measuring and monitoring techniques in a decentralized overall concept for energy generation will grow considerably. With this outlook in mind, the Exhibitor Committee and the Executive Board of the AMA Association for Sensor Technology have put the focus of the SENSOR+TEST 2013 on renewable energy.
Thus, the exhibitors will not only be presenting a broad spectrum of their latest developments in this area at their stands. On the first day of the fair (Tuesday, 14 May 2013), the conference program in Hall 12 is dedicated to this focal topic. Visitors at the SENSOR+TEST can obtain information on the state of the art in energy harvesting and ideas for the future at a special “Renewable Energy” forum, where enterprises and institutes present pertinent innovative applications, products, technologies, and services.
Product Overview of the SENSOR+TEST 2013
The text below is based on the preliminary information given to AMA Service, the fair organizers, before end of January 2013 by the exhibitors. It comprises a preview of products, services, and trends that can be seen and experienced at this year’s SENSOR+TEST from 14 to 16 May 2013. The structure follows the trade fair’s nomenclature.
Overview of Topics:
Optical Sensors / Sonic Measuring Systems
Other Products / Services
The measurement of distance, gap, position, angle, tilt, and attitude – for the most diverse applications – is one of the most often needed tasks. Today, sensors for such measurements can be found in smartphones, machine tools, mobile cranes, and robots. A number of exhibitors at the SENSOR+TEST will be presenting relevant products based on different sensor principles and designs. The offers range from extremely small, multi-axial micro-electro-mechanical systems (MEMS) to hydraulic cam systems (HCS) for wind-power generator shafts.
A dual-axis clinometer with a measuring range from ±25° to ±90°, packed in a plastic housing, is not only rated IP67, but is even resistant to oils, fuels, and lubricants. Measuring errors over the entire range of -40 °C to +85 °C are under 0.5 % at measuring rates of up to 100 Hz. Besides industrial applications, this relative tilt sensor targets construction machines and working platforms. The system is based on a shock-resistant 3-axix MEMS acceleration sensor. , A Chinese enterprise from Wuxi is presenting a MEMS mass-produced inertial sensor, enhanced as an AHRS (Attitude Heading Reference System) measuring system that uses further reference sensors to exactly determine a given 3D. The know-how lies partly in very special algorithms. It can be integrated in higher-level systems by numerous interfaces. The system targets automotive and aerospace engineering applications, but also motion detection in game consoles, for instance. Also from China, but this time from Shanghai is an extremely precise inclination sensor with an accuracy of ±0.01° and an adjustable vibration attenuation. Production makes use of patented automatic testing process that determines a number of parameters, such as linearization, temperature compensation, alignment errors, or crosstalk. Typical applications include platform stabilization, guides for drilling machinery, or tank-inclination control. Another MEMS IC measures the magnetic field along the three spatial axes with an accuracy of ±2 %. With a quiescent power consumption of 100 µA it is suited for electronic compasses, game consoles, or positioning sensors.
Distance, Fill Level
This year there is a noticeable number of suppliers of magnetic displacement and position sensors. For example, magnetoresistive (AMR) sensors, an A/D converter, and a signal processor were integrated in an incremental encoder with a 13-bit resolution. This can be used to detect rotating and linear positions along a magnetic pole strip. The robust array is designed for drive controls in machine tools used under rugged conditions.
From Slovenia there is an absolute measuring magnetic system used for motor control, position, and speed monitoring. It works with two magnet coils, an incremental track with 2-mm poles and a parallel 13-bit absolute track. The response times are designed for highly dynamic control circuits. This supplier’s incremental measuring system uses a self-adhesive magnetic measuring tape and enables processing speeds of up to 40 m/s at a local resolution of 10 µm.
A British enterprise propagates a small contactless inductive position sensor with a high resolution, designed for robots, handling machines, or for dirty or dusty applications. A 12-bit resolution and a sampling rate of up to 15 kHz supports very dynamic motions. The linear measuring range is limited to ±10 mm. Also for harsh and dirty environments is a magnetic tape sensor from Switzerland. At a resolution of up to 0.01 mm, the air gap between sensor and magnetic tape can have a width of 2 mm. Typical fields of application are: motor feedback systems and handling machines. Especially designed for short-stroke drives in places with strong vibrations or rocking, this manufacturer presents a linear Hall sensor that can control distances of up 10 mm with an absolute linearity of ±0.016 mm. The sensor is used as a touch probe or limit switch.
At this SENSOR+TEST, Chinese suppliers will be showing their magnetostrictive position sensors. Measuring ranges from 25 mm to 7.6 m are detected with a repeatability of <±0,001 %FS and a 16-bit resolution and are converted into the usual analog output signals. A Turkish supplier claims to offer inexpensive solutions for most distance, position, and fill-level measuring tasks based on a broad range of potentiometric distance, trip-wire displacement, and magnetostrictive sensors. Also used for fill-level measurements are pressure transmitters, of which the SENSOR+TEST most likely has the greatest offering at a single venue in all of Europe. Visitors will also find diverse DIN compliant inductive measuring probes with hard-metal inserts. These can be adapted by external programmable signal processing to numerous measuring tasks.
Rotary Encoders / Speed Sensors
To measure angles of up to 360° relative to an external magnet, AMR sensors with integrated signal processing for programmable angular resolutions of up to 13 bits are offered at SENSOR+TEST. A sleep mode with a wake-up function enables battery powered applications.
In a different ball park, encoders work in wind turbines. A magnetically coded ring can be clamped directly on shafts of 140 mm to 200 cm with the probe in close proximity. Digital signal transmission over great distances are accomplished by proprietary formats.
On a quite smaller scale, a ring with a diameter of 49 mm can provide 131,072 positions at a 17-bit resolution. This is done by a magnetic system working at a speed of 10,000 r.p.m. with a resolution of less than 0.1°.
For shaft diameters of 30 mm to 44 mm, such as are used in elevators, hollow-shaft encoders are presented in Nürnberg without glass disks, but with a high impact and vibration resistance and a resolution of up to 1,440 pulses per revolution. An overall resolution of 51 bits is attained by multiturn encoders that work without a battery. The number of revolutions is detected and stored by means of the Wiegand effect. Magnetic sampling is also available. Encoders for use with brushless electromotors come to the SENSOR+TEST from Slovenia. Besides an encoder signal, they also provide a commutation signal for up to 8 poles.
The list of mechanical measuring parameters extends from pressure / differential pressure, force / weight to mechanical stress, torque, and density or viscosity. For most of these parameters, visitors at the SENSOR+TEST will find a broad spectrum of sensors or transmitters. Especially for pressure measurement there is no trade fair with a wider range of products and suppliers.
For measuring temperatures up to 200°C, a British manufacturer uses silicon strain gauges, grown epitaxially on a sapphire membrane. These sensor elements are then applied to the pressure-loaded titanium-alloy membrane. This results in an extremely exact sensor that can be overloaded and is very corrosion resistant as well as electrically well insulated and practically hysteresis free. The same technology is used by an enterprise in Nürnberg supplying high-pressure sensors for measuring ranges up 4.000 bar, which are also available for hazardous areas. Made entirely out of titanium are housings of pressure transmitters for measuring the relative pressure of organic or chloride-containing substances. They are especially designed for the requirements of the water and waste water industry.
A wide range of offers for pressure measuring at the SENSOR+TEST has come for years from China. For instance: a highly accurate process transmitter with 4–20 mA analog and a digital RS485 interface that can be parameterized via HART protocol and offers pressure ranges from -0.1 bar to 100 bar. Sensor capsules with a 12.6-mm diameter have been designed for OEM applications. Equipped with a separating diaphragm, they are powered by a constant current and designed for pressures of up to 1,000 bar. Similar models are available for measurements as of 200mbar with titanium diaphragms and titanium or stainless-steel housings.
Besides piezoresistive elements, the transmitters also use capacitive ceramic pressure sensors with their inherent advantages in corrosion resistance and overload stability. , Chinese enterprises are also showing their transmitters with thin-film sensor elements. These are especially designed for vibration and impact resistance. Such transmitters are also available in Germany, especially made for applications in commercial vehicles and mobile working machinery. They can be had with a CAN-bus interface or an SAE J1939 protocol. Sampling rates of up to 1,000/s allow their application in dynamic mobile hydraulic systems. Special models for motor sports can also be found at the SENSOR+TEST. One model is designed for use in security-relevant applications in compliance with Machinery Directive EN13849-1. However, anyone who just wants to take advantage of thinfilm technology can obtain measuring cells in various states – including that of OEM products. , For such requirements, a visit to the SENSOR+TEST is just the thing.
Besides transmitters and in part digital manometers for industrial applications or process technology, there is a plethora of miniature pressure sensors for direct PCB assembly , for instance in medical technology or in heating, ventilation, and air conditioning (HVAC). , The measuring-signal output is often analog, but also available at a digital I2C interface.
Besides measuring elements for relative or absolute pressure, there is of course the broad spectrum of sensors for measuring differential pressure. Here we do not just have the usual – and quite novel – models for process technology, but fully encapsulated miniature sensors.
Also presented in Nürnberg are pressure compensators or hydraulic calibration hand pumps, a number of devices with integrated data logging as reference for sensor calibration. ,
Visitors who wish to have their pressure transducers or transmitters customized to their specifications can do so at a British stand.
Noteworthy in pressure measuring technology are transducers for measuring explosion waves or scanners for profiles of pressure values in wind tunnels or for flight tests. Important in the latter application is the exact correlation of measuring values output in up to 64 channels.
Force, Load, Weight
Visitors tired of cable spaghetti can get a taste of wireless transmission in virtually any hall at the SENSOR+TEST. A case in point is a modular force / weight measuring system: 32 sensors at a distance of up to 200 m can be linked into a network transmitting their measured data to a 433-MHz receiver and then to a PC or laptop running the right software for evaluation. The data can also be transmitted by semi-persistent scheduling (SPS). The sensors are powered by a rechargeable battery with a 1,000-hour capacity.
A Turkish manufacturer is showing an entire product range of different force transducers and load cells. Typical applications are found not only in R&D, but also for storage tanks, silos, loading ramps, and other industrial installations. Strain-gauge transducers for various measuring modes are available: pressure force, pressure / strain, deformation, or shear force. Measuring amplifiers for signal conditioning are also available. Visitors looking for customizations or in need of consultation on special designs will find contacts for force and strain development at the SENSOR+TEST.
Load cells from the Netherlands are made for weights from 60 kg to 60 t and meet OIML R60 for 10,000 to 25,000 measuring intervals. Typical applications are found in process measurement technology, such as for dry material feeders or bulk containers in the food industry. For such load cells, signal-conditioning modules with a digital display and limit relays for mounting on top-hat rails can also be supplied. Analog outputs and digital interfaces (RS485) are available with optional support by Profibus DP, Ethernet, or other systems. Dynamometers can also be seen in Nürnberg with integrated digital displays for semi-static tensile or pressure forces. They have measuring ranges between 200 N and 100 kN.
For system tests or calibration, a handheld measuring instrument can be viewed at the SENSOR+TEST that can evaluate signals from force transducers with TEDS data. The measured force, on an expanded 6 calibration-point TEDS-M, can be precisely displayed or transmitted to a PC with evaluation and data logger functions. Especially designed for web tension measurement and control are new multifunctional measuring amplifiers with 2 to 8 channels and interfaces to Profibus, Profinet, EtherCat, etc. Parameterization is carried out on a touch panel.
The detection of torque is generally no trivial matter, since it required contactless measuring processes or signal transmission from the sensor on the shaft to an evaluation unit. Instead of working with individual strain gauges, a supplier in Nürnberg is presenting a torsion sensor, which is applied to the shaft like a kind of postage stamp. It comprises not just strain gauges, but also a signal-conditioning and telemetry module to ensure signal transmission.
A number of exhibitors at the SENSOR+TEST deal with the detection of surface pressures through matrix sensors. For contact-load analysis, a pressure-sensitive film is placed between the bodies. The film has up to 32×32 (1,024) tactile surface sensors on areas of up to 1x2m². A notebook can be used for evaluations. Typical applications are found in medical technology, on presses, printed circuit boards, car seats, pedals, and door seals, for instance. A detailed analysis of force distribution on an active surface of approx. 130×130 mm² by 44 force sensor per cm² is offered by a Taiwanese enterprise. A variant for bigger areas is used for examining the contact area of tires, for example. Flexible force-sensor foils are also supplied from the United States to simplify fine adjustments of production equipment.
The SENSOR+TEST is where accelerometers, vibration, oscillation, and sound analysis systems are found. This can also be said for speed and flow sensors. In recent years, the offerings have been augmented by suppliers of gyroscopes in MEMS technology. These are commonly used to measure rotation rates, but can also be used to determine spatial position or attitude. We will consider them here as dynamic parameters.
Two separate MEMS sensors – one for rotational speed, the other for acceleration – are encapsulated in a nitrogen-filled SMD component by a British supplier. This combination sensor attains a dynamic range of 300°/s (at a bandwidth of <90 Hz) or 10g (at a bandwidth <190Hz). The sensitivity can be adjusted in dependence of the application. A development module for tracking motion sequences in 9 axes is to be brought by a British exhibitor to the trade fair at Nürnberg. For every 3 axes it has a speed sensor, an accelerometer, and a geomagnetic sensor. R&D for augmented reality and game consoles are deemed potential applications.
A Turkish supplier wants to present a MEMS accelerometer with the lowest noise worldwide in a measuring range of ±3g at the SENSOR+TEST. Also to be presented are seismometers, comprising turnkey multichannel systems for earthquake detection or geological research.
Coming from China are gyroscopes in MEMS technology with a bandwidth of up to 80Hz. Their main area of application is navigation, vehicle stabilization, and robot control, but are also to be used as sensors for image stabilization in cameras. Another Chinese supplier focuses on acceleration sensors. The product range includes an hermetically sealed piezoelectric transducer with a sensitivity of 50pC/g for measuring jet-engine parameters. Low-weight IEPE/ICP models with 10mV/g are available for general applications of up to ±500g, even lighter with only 3g – and without electronics, but with a charge output – or with a voltage-generating piezomaterial as a sensor, only 0.4g. For application in wind turbines, oil pipelines, and steelworks or for monitoring bearings, more robust models are needed with magnetic brackets in noncorrosive housings and typically a 100mV/g output signal.
Triaxial accelerometers are designed for seismic measurements or for simulation platforms for earthquakes, in buildings, or on bridges. They are also available as monoblock sensors, housed in a titanium case, weighing slightly over 7 g, and having a sensitivity of 5pC/g – or as a 1-g stainless-steel model with a 0.6pC/g sensitivity.
Important considerations for all accelerometers are not only the measuring, temperature, and frequency ranges, but also the signal-to-noise ratio and the cable and connector types. The concepts behind the terms “accelerometer” and “vibration transducer” are not all that central for practical measuring results. The latter are used in machine monitoring, available as very robust models for continuous monitoring with process-capable 4-20mA signal output. For engine test rigs, a single and 3-axes vibration transducer is presented in Nürnberg with an integrated 5-kHz low-pass filter that attenuates unwanted high-frequency components. The transducers supply 50mV/g at up to 160°C. According to the supplier, the smallest and lightest accelerometers that can be used at up to 200°C are those with 0.25g, which have a sensitivity of 0.4ppC/g. These are primarily used for modal analysis on models or electronic components and are adhesive. For temperatures between -45°C and +650°C, vibration sensors for frequencies from 30 to 2,000Hz are specified. They have a sensitivity of 5ppC/g and are designed especially for measurements on turbines.
Without any weight at all or even a cable, for that matter: vibrometers working with optical measuring systems. These can be applied to all kinds of molded parts and from a safe distance on wind turbines or on power-line poles, for example. Using 3Dscanning vibrometry, finite-elements models can be optimized or critical vibration states on transformers can be characterized.
Completely different requirements need to be met for applications in mobile electronics: programmable measuring ranges between 2g and 8g, SMD housings for automatic mounting, etc. This is about the free-fall detecting laptops or recreational pedometers – or tapping commands on a smartphone.
Whenever operating temperatures rise – for instance in automotives or the aerospace industry – let us say to 800°C, water-cooled designs with output signals of up to 100mV/g are needed. With a flow rate of 0.5l/min, the temperature inside the sensor can be limited to 35°C.
It should be mentioned here that plenty of measuring accessories, such as charge amplifiers, impact hammers, calibration devices, and so forth are also available at the trade fair. There are also measuring microphones and acoustic cameras. Rather exotic is a charge amplifier offering a bandwidth of 100Hz to 10MHz. It is made for measuring blast waves or frequencies in a shock tube.
A premiere at the SENSOR+TEST will be a sensor for the speed of sound, or more accurately acoustic particle velocity, made in MEMS technology in the Netherlands. The motion of particles is determined by the temperature difference between two taut and extremely thin platinum wires. This is supposed to greatly simplify acoustic testing.
Mass flow – of gasses or liquids – is a parameter associated with a big product range at the SENSOR+TEST.
A Swiss enterprise will present its new flow-sensor line for liquids in the microliter and milliliter range. The patented process enables a straight flow channel without any obstruction. With measuring ranges between 0.0008ml/s and 5ml/s, expected applications are in medical technology and the pharmaceutical industry. For artificial respiration or anesthesia in hospitals or blowpipe control, bidirectional mass flow meters of up to 200slm can be used that work with a thermal-flow sensor element. A magnetic-inductive process is used by universal flow meters for flow speeds up to 10m/s for pipe diameters of up to DN400. Various functions can be adjusted externally via a digital input, which considerably increases the flexibility for process applications. This manufacturer will also present an individually configurable measuring system in Nürnberg that can process the signals from two flow meters. It can be used in water treatment facilities or food production.
This year two of the world’s most important suppliers of platinum resistance temperature sensors from Germany will be exhibiting at the SENSOR+TEST. Also, one of the most important makers of NTCs from China – along with many other suppliers for specialities in temperature measuring technology – will be there. As far as size and variety go, the market for temperature sensor seems to be without limits – and that is exactly why visitors at the SENSOR+TEST find what they are looking for.
There are sensors from Switzerland for PCB assembly that only need a surface area of 3×3 mm², can measure at temperatures from 5°C to 60°C with an accuracy of ±0.22 K, and are equipped with an I2C interface. A similar component requires 4×4 mm², works with a 24-bit A/D converter, and outputs its data via an I2C or SPI interface. It provides an accuracy of ±0.1K for temperatures between -5°C and +50°C. Platinum chip temperature sensors in a low-cost variant with nickel connection wires will be shown that are supposed to better reach markets from automotives to household appliances.
Quite a contrast is offered by a supplier of high-precision glass-coated resistor thermometers that are only custom-made. Dimensions, connections, and even immersion depth can be specified. The measuring ranges are between -200°C and +45°C. Also manufactured strictly to customers’ specifications and available in small quantities are bimetal switches for low temperatures down to -20°C. Until recently, such models were only available upwards of +60°C. The advantage of these autonomous switches is their functional simplicity. With tolerances of approx. ±3K, the snap dome reliably triggers an electrical switching operation when the nominal temperature is reached – done.
A completely different picture is presented by the wireless SAW temperature sensors: The ceramic substrate of the finger structure for sampling the surface waves requires 9.8x3mm² for the present version. The sensors are adhesive and can take temperature measurements on rotating parts or inside of generators and ovens between 15°C and 165°C. A remote inquiry pulse activates the surface waves and a response pulse provides the measured values. Contact is very important in another application for which spring-loaded screw-in temperature sensors were developed: Contact pressure reliably ensures a stable thermal coupling to the measured object. This design will be shown at the SENSOR+TEST with various electrical connection heads.
With 900 million NTC thermistors per year, one of the big suppliers of such sensors in China plays in a different league. The ISO-certified and often awarded enterprise will present its palette of NTCs, PTCs, and varistors at the SENSOR+TEST in May. The applications range from temperature compensation or control to precision measurements. By the way, the annual production capacity is now stated to be one billion sensors.
Beyond the diverse sensor elements for temperature measurement, a great variety of off-the-shelf temperature sensors can be seen in Nürnberg – as can dedicated transducers for assembly of sensor heads, wall and top-hat rails. , There will also be a plethora of calibrators with convenient data acquisition and process interfacing features. Thanks to Peltier technology, dry-block calibrators are now available for temperature ranges from -55°C to +200°C. With block diameters of up to 60mm, a number of temperature probes can be calibrated simultaneously.
Rounding off this section is a typical specialty for the SENSOR+TEST: The heat flow between two contact surfaces can be measured by a temperature measurement film. It is applied in conjunction with a pressure measuring film for testing the evenness of the sealing-strip surface of plastic bags at temperatures between 150°C and 210°C.
Optical Temperature Measuring Processes
In steelmaking and generally in the process industry, contactless optical temperature measuring methods have been in use for quite some time. All the more reason to check out the SENSOR+TEST, where traditionally a number of suppliers present the state of the art. One such item is a UV pyrometer designed for the 400-nm wavelength. Used in LED production, it can measure temperature directly on the wafer surface and – in conjunction with an integrated laser reflectometer – the layer thickness and growth rate of a gallium-nitride layer during epitaxial deposition. Among the many suppliers of IR thermometers, one Chinese exhibitor must be mentioned, whose products can be applied for measuring ranges from 0°C to 300°C and 0°C to 800°C at an accuracy of approx. 2%. They offer analog or digital (RS485) output signals. Water-cooled housings are available for process-linked assembly.
Talking about very low temperatures – at least for optical processes – of about -50°C to +200°C, thermopiles come to mind that have integrated IR filters (8…14 µm) as sensor elements.
A different kettle of fish are thermography cameras. As is the case for visible-light cameras, the number of pixels on the sensor surface increase from year to year. Sequences of dynamic images with a resolution of 2,048×1,536 pixels lets even very minor defects on large objects become visible. The GigE-Vision-Format, well established in industrial image processing, is used as an interface. A cooled focal plane array enables a spatial resolution of 1,280×1,024 pixels and a thermal one of 0.02 K. It is used in an externally triggered high-speed camera that can provide 390Hz frame rates. With motor-driven lenses, electrical components can be inspected in detail.
This section will deal primarily with moisture in gasses. Needless to say, sensors for smoke detection, barometric air pressure, or solar radiation can all be found at the SENSOR+TEST.
Nevertheless, we will first take a look at a complete meteorological station. An American supplier has put sensors for all the major parameters together: air temperature, barometric air pressure, and wind speed as well as wind direction – the latter measured ultrasonically. With an optional GPS, for use on ships for instance, the true wind speed can be determined. Measured values are output digitally to an RS232/422 interface or a CAN bus. For high-precision measurement of air humidity, a digital psychrometer with two Pt100 temperature sensors provide a resolution of 0.001K. A calibration error curve is stored in the connector and can subsequently be evaluated by a connected display unit. The device also has a sensor for barometric air pressure, the values of which are used in computing relative humidity, dew-point temperature, absolute humidity, vapor pressure, and enthalpy.
When we are not dealing with measurements in the ambient air, but say in natural gas, we should take a look at a device from England that can determine the dewpoints of hydrocarbon and water. This supplier also has hygrometers that measure trace moisture up to 0.1ppmV (-90°CTd) by way of chilled mirror dew without the need for external cooling. These are also used as reference devices in motor test rigs, for instance. The separation of sensor and evaluation unit makes them also suited for measurements in climatic chambers, e.g. for environment tests. Complete analog signal conditioning in a combined temperature / humidity probe in a stainless-steel housing allows operation in air ducts with a corrosive environment at temperatures up to 150°C.
In a different world – that of smartphones and mobile handheld devices – the smallest moisture and temperature sensor was developed in Switzerland, or so the manufacturer claims. On an area of 2x2mm², relative humidity between 0…100%RH and at temperatures between -30…+100°C are measured. For handhelds with the Android 4.0 operating system there already is an application programming interface (API) for “mobile health” and similar apps.
Not quite as small and mobile in a different way are climate data loggers with various memory capacities. These are used in refrigerators and containers with preset measuring cycles as evidence of (un-)broken cold chains. A number of models using this kind of climatic sensor technology can be found at the SENSOR+TEST.
We conclude this section with an application in the realm of renewable energy: When filling up a the tank of car running on natural gas, measures must be taken to ensure that the dewpoint is not reached at the filling pressure of 250 bar. Just how dry the gas really is can be determined with a special nonhazardous dewpoint hygrometer, which can also be used by service technicians to detect trace moisture.
Optical Sensors / Sonic Measuring Systems
The spectrum of optical sensors at the SENSOR-TEST is not really bigger when the parallel conferences, OPTO and IRS², are being held, although they are dedicated to presenting research results in optical and infrared measuring technology. Their venue, however, does document the importance of optical sensors to sensor technology per se. The areas of application for optical sensors are very diverse: We have gas and particle measuring, fluorescence and analysis, spectroscopy, temperature measuring, motion detections, high-resolution positioning systems, etc. A major consideration is always sensitivity and the signal-to-noise ratio.
For many applications in medical technology and bioanalytics, highly sensitive UV detectors are required. At the SENSOR+TEST unique avalanche photodiodes with active areas of 0.5…3.0mm diameters are presented that have been optimized for wavelengths as of 250nm.
Photodiodes made of SiC are blind when it comes to sunlight and were optimized for wavelengths of 270nm. With an active area of up to 5mm² they are used for tracking applications. Measuring modules on the optical bench at the SENSOR+TEST include GaP photodiodes (190-570nm), Si photodiodes (200-1050nm), and InGaAsPIN photodiodes (800-2200nm) – all with corresponding current amplifiers. For the infrared portion of the spectrum there are low-cost product lines of thermopile-infrared detectors that are used in the areas of gas analysis, process control, or security. Last, but not least, users of photomultipliers will also find interesting novelties at the fair.
Cooled and uncooled matrix sensors with 320×256 pixels made of InGaAs are to be found in Nürnberg for application areas in industrial testing technology. The same supplier has CCD image sensors with spherical surfaces for applications in image processing. They boast 16 M pixels, which greatly simplifies the imaging optics. Also, there are especially low-noise 100 M pixel image sensors in CCD technology with a split-frame architecture that can be combined in compact housings to entire sensor mosaics, which in turn can be used in astrophotography or satellite monitoring.
In the application of optical sensors, as a rule, optical windows are used to limit the sensitivity range of the sensor. This window is attained by thin coatings, the first being antireflex layers to allow the full penetration of light into the lens. , GRIN lenses are used to attain a particularly low-loss coupling of optical fibers to detectors. Further coatings on the optical components are used as low-pass, high-pass, or band-pass filters with steep edges and low losses. In this area of application, an enterprise from China is offering a further coating that targets the lotus effect. Without changing the optical properties, this layer is supposed to drastically reduce moisture and dust particles of optical devices and thus considerably improve the long-term stability of the measuring characteristics. This enterprise also offers filter lenses in which optical windows are brought into the light path by directly coating the lens and thus providing a further optical component. After consultation with the OEM customer, ready-to-use filter capsules can be provided that are then directly mounted on the sensor chip. Obviously, good communications between supplier and user is a prerequisite for a successful application of optical components.
In keeping with the motto of this year’s SENSOR+TEST, one exhibitor is to present special noise-level testing wind turbine power generators. According to the exhibitor, such testing has been carried out with these devices on a testing site in Gangwon, South Korea. The acoustic measurements include weighted sound power levels, third-octave band levels, and tonality. For determining the noise exposure of persons according to IEC 61252:2003, a noise dosimeter was developed. The device is worn by the test subjects directly on the body and it continuously records the noise level without hindrance. The noise values are obtained with a special read-out device and corresponding software.
For sound and vibration measurements, a modular data recorder and signal analyzer are to be presented in Nürnberg. The device has a 10-hour rechargeable battery and comes without a hard drive or fan as it is especially designed for mobile use. Up to 16 input channels can detect signals with a 24-bit resolution. These are stored in an internal flash memory for parallel analysis. For of environmental noise measurement there are other devices with large memory capacities. They are designed as short-term or long-term monitors, can quickly analyze the data and generate a report.
Sensors for determining the concentrations of toxic, explosive, or other gases with various methods have been a central topic at the SENSOR+TEST for years. The exhibitor press releases in advance of the fair this year have focused on optical processes. Also, a broad spectrum of wet chemical sensors, such as for pH value or conductivity, can be expected.
Not just individual gases, but complete odor patterns can be detected by a mobile measuring device. These can be recorded over a number of weeks together with moisture and temperature values. The evaluation of the complex signal patters enables optimization of process parameters for deodorizing systems or it can provide data for materials development in the textile or cosmetics industries.
According to the manufacturer, the currently smallest CO2 sensor works with IR absorption, a sophisticated autodiagnosis concept, and a UART interface. Target applications are HVAC. A safety switch made by the same supplier monitors dangerous CO2 concentrations in the vicinity of heating equipment up to 32 %vol. For greenhouses or office buildings, a Chinese manufacturer is presenting similar products for measuring CO2 concentrations complemented by electrochemical CO sensors. A German HVAC technology supplier has expanded his product range to include transmitters for detecting CO2 concentrations.
Visitors will, however, not only find finished products for gas measuring technology, but also elementary sensors, such as a two-channel detector in a TO-18 housing with a deflector surface of 1.4mm². The first prototypes were set up with filters for 4.27µm/170nm (CO2) and 3.98µm/90nm (reference channel). Filter combinations for measuring other gases, such as methane, are in the planning stage. , Such sensors can be used in NDIR platforms that can be configured for certain types of gas. Besides integrated temperature and pressure compensation, low-noise electronics for signal amplification and linearization of characteristics is available. The measuring modules can be used for concentration measurements of SF6 or refrigerants (traces), in emission technology (CO/SO2), or for controlling the fruit ripening process (ethylene).
For the detection of methane in the vicinity of biogas plants, a handheld measuring device is to be presented in Nürnberg that can make observations at a distance of 60 m with the corresponding laser light. Rather than using IR detectors with gas-type filters, it is also possible to use lasers (VCSEL) for the required wavelength. An ingeniously designed measuring cell attains an optical distance of 36m to intensify the interaction of gas and laser light and to increase the sensitivity. Such long-path gas cells are used to analyze trace components in gas samples. A highly sensitive optical measuring process for determination of nitrogen oxide (NO/NOx) between 10ppbV and 5,000ppmV is offered by the chemoluminescence of NO in reactions with ozone. The latter is generated by high voltage discharges.
A Swiss supplier of more than 200 gas sensors for 20 different types of gas has expanded his product line with an electrochemical oxygen sensor for concentrations in the ppmV range. In a 4-electrode version, concentrations can be measured up to ppbV ranges. To measure the oxygen concentration in nitrogen, air, hydrogen, and diverse gas mixtures, devices are to be presented at the SENSOR+TEST that work with measuring cells on the thermo-paramagnetic principle and are NAMUR compliant. Models for measuring nitrogen or biogas production or for monitoring oil storage tanks range from transmitters with limit indicators to complex analyzers. Especially for the application in biogas facilities, another exhibitor at the SENSOR+TEST is showing electrochemical sensors for oxygen, present in aggressive gas mixtures, and sensors H2S, which are resistant against hydrogen and have hardly any cross-sensitivity to ammonia. A British manufacturer has wisely put his latest sensors in MEMS technology for methane and other combustible gases or vapors in an explosion-proof housing.
Visitors to the trade fair in Nürnberg will find diverse components for gas measuring devices, such as optical fibers for the transmission of infrared light, including hermetically sealed feedthroughs in vacuum or overpressure chambers. For Raman spectroscopy there are diverse excitation sources, especially ones with narrow bands, and Bragg gate stabilized laser sources for 647nm, 785nm, 830nm und 1064nm. From Saint Petersburg in Russia we have special high-efficiency LEDs for the middle infrared range from 1.6 µm to 5.0 µm, the development of which was advanced by Rusnano. Operating temperatures of up to 150 °C and a modulation bandwidth of up to 100MHz are attained. Visitors will also find micro-sized membrane pumps, designed for a long service life. They are available in portable gas-warning devices or in medical technology.
At the SENSOR+TEST one entire hall is dedicated to measuring and testing technology. Here, just about everything can be found from handheld devices to complex measuring systems for test rigs and construction inspections as easily as process instrumentation. Then there is mobile measuring technology – mainly for automotive applications. Visitors can experience these live in test drives.
Arriving from Turkey, a country often struck by earthquakes, is a wireless system for monitoring building and bridges. The signal conditioning of the accelerometers is performed in robust network modules that send their data including GPS location via radio transmission to a central measuring PC for data processing and evaluation. The system has a 16-bit resolution. In a similar system from the same supplier, the signals from the sensors for diverse parameters with a 16-bit resolution is conditioned in individual radio modules and is then transmitted over a wireless mesh network to a central computer, where they are processed by data-acquisition and analysis software. Also decentralized, but linked to an industrial Ethernet network, is a system that performs not only measuring tasks, but control and automation tasks as well. The components are autonomous and can handle a number of control loops or record data without using the resources of the central computer.
Besides PC measuring systems with measuring amplifiers, data loggers, and evaluation software for all kinds of examinations in industry and research, dedicated multichannel measuring systems are presented at the SENSOR+TEST. These can collect the measuring values from straingauges, force or pressure transducers with a 24-bit resolution, or they can perform 8 leisurely measurements per second for all kinds of laboratory measuring tasks. Also in this category is a system that works with completely autonomous measuring modules and can do without a host PC. If that is too slow for anyone, there is a broad spectrum of transient recorders to choose from that occasionally manage 4 million measurements per second. For tried and proven individual systems, new modules are presented, such as an A/D measuring board with 8 analog, fully differential, simultaneous input channels, the potential inputs of which are separated for up to 500 V. That is why the board is particularly suited for measuring solar cells, batteries, fuel cells, etc.
At every SENSOR+TEST one can find the state of the art in dataloggers for the most diverse tasks. Quite up to date is a device for medical applications that boasts wireless live transmission of measured values and cloud storage on a server. Tried and tested miniloggers from Switzerland perform documentation and monitoring tasks in 30 countries. Now they can also operate numerous sensors for the same parameter and store signals from pressure sensors. More for everyday processing are videographic recorders for process values displayed as pen lines and stored in a tamperproof memory. With Food and Drug Administration (FDA) approval, they can be used in the food industry to document the preparation of products. For special applications in liquid analysis, the same supplier offers a multichannel measuring device that autonomously performs the four required tasks: measure, display, control, and record. This is about parameters, such as pH value or Redox potential, electrolytic conductivity, ultrapure water resistance, temperature or disinfectant parameters, such as free chlorine, chlorine dioxide, ozone, hydrogen peroxide, and peracetic acid or just flow quantity. However, there are loggers in Nürnberg for completely different signals, such as for CAN data.
Oscilloscope recorders are to be presented for service work in the field. These can be easily carried in hand luggage and are operated on site with rechargeable batteries. They measure ±500 VDC, thermoelectric voltages (emfs), or digital signals and offer the functions of a transient recorder as well as that of a measuring data acquisition system or a recorder.
Among measuring amplifiers there is a specialty, originally intended for highly dynamic heat-flow observation with thermocouples or signals in the ultrasonic range. A voltage amplifier for max. 35 mV on the input and a bandwidth of up to 10 MHz can also be used as a preamplifier for oscillographs or transient recorders. Not quite as fast is a precision measuring device for application as an HVAC or lab instrument, datalogger, or display unit with limit-value monitoring. The calibrated sensors can be replaced while calibration data is safely stored in the plug by the device.
Visitors at the SENSOR+TEST will not have to search long for hand-held calibrators for factory calibration. Such devices supply voltages up to 25 V, currents up to 22mA, and simulate thermocouples according to DIN or the behavior of resistance thermometers.
At the end of this section we need to point out a very special amplifier chip. This component uses a low-power digital signal processor with a 48-bit resolution and a 4-kB program memory, thus enabling individual multipoint calibrations. Up to 8 capacitive sensors can be connected and still attain a measuring rat of 500kHz at a resolution of 20bits.
No measurement or testing configuration can do without software today. This is reflected by the press releases of the exhibitors in advance of the SENSOR+TEST. An enterprise from Berlin thus offers general software for project management that creates a cost plan, manages resources, and provides a ticket system for projects requiring much time for communication.
There is a program from the Netherlands for visualizing stationary sound fields over a broad frequency band. The user can compensate phase differences between sources, carry out manifold analysis, and display the results graphically. A Turkish measuring technology supplier is represented at the SENSOR+TEST with a number of program packages, including general data acquisition software for dynamic measurements. When triggered by an event, the program initiates a graphic display of the measured values and continuously determines limit and mean values. The calibration settings are used to define the individual signal sources and scaling. This supplier also presents software for analysis of available measuring data and creation of reports. The program has numerous functions for data analysis. It targets monitoring stations that have to submit reports regularly.
For practice-oriented users is software that goes back to the 80ies, when DOS had its heyday. Today it has attained maturity for measurement, storage, and analysis tasks. The programmers consider their application a utility for visualizing physical processes on a PC and providing useful results. More specific is an update provided by a supplier of a magnetic field camera. The measuring and analysis software for the inspection of permanent magnets – as used with Hall sensors in great quantities – was completely revised and expanded with a number of additional functions. A special software application was developed in France for material testing with force and torque sensors.
It can generally be expected that all major and minor suppliers of measuring systems at the SENSOR+TEST will present updates to their software packages.
In a way, testing technology can be seen as a combination of the key exhibition areas, sensor technology and measuring technology. Thus, it is an ideal complement to these areas, which in turn need a high degree testing technology for their development and quality assurance. So what better place to present and get acquainted with the state of the art in testing technology.
Impressive as ever are the presentations by the two big suppliers of test chambers. , There are special EMC test chambers that have an electromagnetic protective shield around the test piece, the metallic shell and the electrical and mechanical feedthroughs ensuring that the shield is upheld continuously. As a test process, environmental stress screening (ESS) is considerably more informative than conventional burn-in tests because the stress due to high temperature gradients of up to 70 K/min in the respective test chambers show the weaknesses of electronic components with greater degree of certainty and much faster. HALT/HASS systems for accelerated endurance tests are fitting additions. The Highly Accelerated Life Tests (HALT) are performed in the prototype phase with the objective of optimizing the design. The Highly Accelerated Stress Screen (HASS) is a quality assurance measure in production. Both are available with integrated vibration tables. A special case is a test system for lithium-ion batteries that can not only generate the required temperature changes and vibrations, but also exactly specified corrosion effects and pollutants. With temperature differences of up to 300K between two chambers of a test cabinet, up to 1,000 temperature shock cycles can be carried out without needing to defrost.
As a worldwide novelty, a climatic test cabinet with an integrated robot is to be presented at the SENSOR+TEST. It targets the automotive industry and medical technology and can be of interest in the development of household appliances, where the service life of the material is not as important as functionality and haptic properties.
Remarkable are climatic chambers that imitate real life according to standards and with cyclically changing temperature, variable humidity, or stress by vibrations and salt spray. Such chambers are of great interest for automotives, but also for suppliers of photovoltaic or off-shore systems. Anyone who has seen enough products at the SENSOR+TEST can go find service providers that perform these very tests with plenty of experience. In their laboratories they can generate the most diverse environmental effects, such as climate, impacts, vibrations, underpressure, mechanical stress, chemical effects, UV radiation, and fire or they can carry tests for the various IP protection classes. Here, a vibrating table can easily turn into a 55-kW vibration system. Laboratory equipment can be smaller as well. For instance, there is a motorized torsion testing device from France designed for tests on rotary knobs, valves, or controls.
An important consideration for many sensors used in industrial applications and in process technology is resistance to vibration. Vibrating tables of all sizes can be seen in Nürnberg with electromechanical or servo-hydraulic drives. A novelty here is a multi-sinus excitation facility which subjects the test piece to stress with a number of frequencies at different levels. This can reduce the required duration of endurance test to a fifth.
For modal analysis impulse hammers are to be presented in Nürnberg that are equipped with various IEPE sensors, but complete measuring systems as well, when modal analysis on buildings in earthquake prone regions are necessary.
Condition monitoring in this context is a topic for the SENSOR+TEST: for example, monitoring roller runnability with (contactless) microphones as an alternative to the application of vibration sensors. Another case in point is a teleservice module that continuously records operating data including the GPS position of floor-mounted vehicles. In case of any irregularity, it sends a report via wireless transmission. An almost heavenly monitoring system was developed in Karlsruhe: Extensive decentralized systems or local systems, such as wind turbines, that determine condition per sensors, can pass their data to a cloud system. The software continuously looks for exceptions and systematic deviations. How exactly that works is explained in a forum presentation. Another enterprise offers a complete solution for Internet-supported remote monitoring and reporting (communication and control) of systems with a serial interface. More terrestrial in nature is the communication of components via field bus. The trouble is they do not all talk the same language. That is why there are gateways at the SENSOR+TEST that enable communication between LONTalk, CANopen, Modbus RTU, and Modbus TCP.
Three special test applications will conclude this chapter. The first deals with nip width. This is a measure used in the adjustment of rollers in printing machines. The procedure can be very time consuming, but can be significantly reduced and documented by a suitable analysis system. With up to 15 sensors between the rollers, the evaluation program shows graphically the deviations and supports fine adjustments. The second application is for testing explosives: A highly dynamic transducer for pressure waves and heat flow as well as a dynamic amplifier and a transient recorder are needed. These are then used to detect the explosion speed or burn rate of rocket fuels. And last, not least, the third application: testing of fiber compounds, as used in the area of electromobility or wind energy. Using a new process, the ultrasound waves can be coupled to the test piece without coupling liquids – a defined air gap is sufficient. This greatly simplifies tests for delamination, cavities, and inclusions.
Other Products / Services
A camera from Belgium is used to measure magnetic fields. Applications are in development, production, and quality assurance of permanent magnets, as are often used in sensor technology, automotive engineering, and medical technology. The coin-sized camera module contains an array of more than 16,000 Hall sensors.
Sensor surfaces can be modified with underpressure plasma systems in such a way that the separation of difficult substances, such as nano-tubes (CNTs) or polyethylene powder, becomes possible. Such systems are presented at the SENSOR+TEST.
Piezo activators in various models, including a piezo drive, are used in optics, medical technology, biotechnology, and micro-fluidics in great quantities. Developers of products in this area will find ample offers at the SENSOR+TEST.
Always an important subject for sensors is that of glass-metal feedthroughs in the packaging industry. That is why there are always some suppliers at the SENSOR+TEST that offer such feedthroughs for temperature ranges between -180°C and 500°C at pressures of up to 3,000bar.
Services / Calibration Laboratories
Services also play an ever greater role at the SENSOR+TEST. A Belgian enterprise, for example, offers all stages of ASIC designs, from concept creation, design, and layout to prototypes and production. Suppliers of optical coatings for interference filters (gas analysis), antireflex coatings, holographic gratings (laser tuning), or lotus effect coatings come from Sweden or China. , Besides diverse suppliers of calibration devices for various parameters, there are a number of certified laboratories that offer their services in Nürnberg, for instance for temperature sensors or for pressure transducers.
Besides the special forum on this year’s focal topic “Regenerative Energy”, the SENSOR+TEST 2013 will also offer a well-staffed topic stand dedicated to “Sensors and Systems for Image Processing.”
For all parties involved in sensor, measuring, and testing technology there is a place to be in from the 14th to the 16th of May, 2013, in Nürnberg: the measuring fair SENSOR+TEST. This trade fair with 550 suppliers, two forums for company presentations, an action area for live demonstrations as well as a number of conferences offers efficient and comprehensive technical information.
[info] www.sensor-test.de [/info]