Category Archives: Sensors

In-Circuit Monitors for Electronic Devices

During a chip’s lifetime, there can be a wide variety of issues cropping up. Engineers are using sensors that can address them. As the semiconductor ecosystem touches a wide application space, sensors, and in-circuit monitors are playing an increasing role in managing the silicon lifecycle, thereby improving its resiliency and reliability.

Engineers are expecting a drastic improvement in the reliability of electronic devices with the addition of these sensors and in-circuit monitors. These expectations are due to a combination of sensor placements in true system-level design, in- and on-chip monitors, and an improvement in data analysis.

In the future, with engineers placing more monitors and sensors at strategic locations for collecting data, the combination, and analysis of this data is likely to increase tremendously. In addition, this will lead to a much more detailed understanding of what goes wrong in real time in the life of a semiconductor. Important to note, this is likely to open the door to recovery schemes for keeping devices functioning until they are due for replacement or repair.

All of the above depends on the complexity of the product. Although some regulatory standards for miniaturization are under study, the complexity of the product drives the use of sensors and in-circuit monitors. With consumers wanting greater capabilities in their hands, the requirement is going to increase substantially.

Although users were not interested earlier in concepts like resilience, predictability, and observability, things are changing fast. Chip architects are paying more attention to how systems and devices behave over time, including issues such as silent data corruption. Where earlier, it was hard to articulate the business reasons for such inclusion, chip architects are realizing there are missing pieces. While it is still a tussle between the why and how much, the realization is dawning that it is impossible to have all the computing resources or complex monitors-on-chip that can tackle all scenarios. Especially when such additions need real estate and power to function.

Designers are beginning to realize that advanced design techniques, in conjunction with manufacturing complexities and the latest process nodes, are leading to new challenges. These challenges appear as variable power consumption and affect the useful life of the semiconductor. The power consumption pattern and performance characteristics of a chip change as it travels along the silicon value chain. The variation starts with the pre-silicon design, moving on to new-product bring-up, to system integration, and finally, to its in-field usage.

Monitoring the way a chip degrades over time, can throw light on many types of semiconductor failures, especially with BTI or bias temperature instability. Using in-circuit monitors, it is now possible to measure areas that show performance and power degradation, on-die temperature variations, and workload stress, and monitor die-to-die interconnects for heterogeneous designs. Mission-critical systems define specifications such as safety and reliability as the key differentiating parameters. Moreover, with device functionality degrading over time, it is necessary to evolve tests that include lifetime operation as well.

The industry is now widely adopting an approach that includes more and more sensors and in-circuit monitors for electronic devices to monitor the most prominent slack paths. 

Modern Smoke Safety Sensors

The CN-0537 is a modern smoke detector with a design complying with the specifications outlined in UL 217. The design is based on fire data that researchers have collected at the smoke testing facilities of the Underwriters Laboratories and Intertek Group plc. The design uses the integrated optical sensor ADPD188BI and an optimized smoke chamber. It has a single calibrated device for sensing and measuring smoke particles. 

The design also uses a smoke detection algorithm that UL has tested and verified. This facilitates OEMs in reducing their product development time and thereby delivering their product designs more quickly.  The hardware design has a form factor resembling the Arduino board, and this includes an ADICUP3029 microcontroller development board apart from the CN-0537 smoke detector.

There are two basic designs popular for smoke detectors. One is the ionization type which uses radioactive materials to ionize the air while checking for electrical imbalances. The other is the photoelectric type that checks for current in the photodetector caused by light reflecting off airborne smoke particles and falling on the photodiode.

Although experts recommend a combined solution of both types, the improved reliability of the photoelectric smoke detector makes it more popular. It is faster in detecting common house fires and has a smaller response time to smoldering fires.

The optical module ADPD188BI is a complete photometric system. Its design is specifically meant for smoke detection applications. Rather than the conventional discrete smoke detector circuits, using the ADPD188BI makes the design significantly simpler. This is because the integrated package contains two LEDs and two photodiodes, along with an analog front end. The module utilizes a double-wavelength technique. The two LEDs emit light at different wavelengths—blue light at 470 nm, and infrared light at 850 nm. The LEDs also pulse at two independent time slots, and any particulate matter present in the air scatters the transmitted light back into the device.

The scattered light reaches two integrated photodiodes, which produce proportional levels of current. The analog front electronics digitize this output current. As the optical power from the LEDs is maintained constant, any increase in the ADPD188BI output over time indicates that airborne particles are building up.

The response of the ADPD188BI photometric sensor is a ratio of the input optical power to the transmitted optical power. The manufacturers refer to this as the power transfer ratio or PTR and express it as nW/mW. PTR is a more meaningful parameter than the raw output, as it is independent of the actual hardware settings.

The ambient temperature affects the response of the ADPD188BI system. As the shape of the temperature response curve can vary for the blue LED depending on the amount of current in the LED, it complicates matters further. The temperature response curve of the infrared LED is independent of the LED current.

The CN-0537 smoke detector has a temperature and humidity sensor that monitors the conditions, in real-time, within the chamber right next to the optical module ADPD188BI. This helps to determine the value of the relative response. The software helps with temperature compensation.

Cooling Machine Vision with Peltier Solutions

The industry is using machine vision for replacing manual examination, assessment, and human decision-making. For this, they are using video hardware supplemented with software systems. The technology is highly effective for inspection, quality control, wire bonding, robotics, and down-the-hole applications. Machine vision systems obtain their information by analyzing the images of specific processes or activities.

Apart from inspection systems, the industry also uses machine vision for the sophisticated detection of objects and for recognizing them. Machine vision is irreplaceable in collision avoidance systems that the next generation of autonomous vehicles, robotics, and drones are using. Recently, scientists are using machine vision in many machine learning and artificial intelligence systems, such as facial recognition.

However, for all the above to be successful, the first requirement is the machine vision must be capable of capturing images of high quality. For this, machine vision systems employ image sensors and cameras that are temperature sensitive. They require active cooling for delivering optimal image resolutions that are independent of the operating environment.

Typically, machine vision applications make use of two types of sensors—CCD or charge-coupled devices, and CMOS or complementary metal-oxide semiconductor sensors. For both, the basic functionality is to convert photons to electrons that are necessary for digital processing. Both types of sensors are sensitive to temperature, as thermal noise affects their image resolution, and thermal noise increases with the rising temperature of the sensor assembly. This depends on environmental conditions or the heat generated by the surrounding electronics, which can raise the temperature of the sensor beyond its maximum operating specification.

By rough estimation, the dark current of a sensor doubles for every 6 °C rise in temperature. By dropping the temperature by 20 °C, it is possible to reduce the noise floor by 10 dB, effectively improving the dynamic range by the same figure. When operating outdoors, the effect is more pronounced, as the temperature can easily exceed 40 °C. Solid-state Peltier coolers can prevent image quality deterioration, by reducing and maintaining the temperature of the sensor to below its maximum operating temperature, thereby helping to obtain high image resolution.

However, it is a challenge to spot cool CCD and CMOS sensors in machine vision system applications. Adding a Peltier cooling device increases the size, cost, and weight. It also adds to the complexity of the imaging system. Cooling of imaging sensors can lead to condensation on surfaces exposed to temperatures below the dew point. That is why vision systems are mainly contained within a vacuum environment that has insulated surfaces on the exterior. This prevents the build-up of condensation over time.

The temperature in the 50-60 °C range primarily affects the image quality of CCD and CMOS sensors. However, this depends on the quality of the sensor as well. For sensors in indoor applications just above ambient, a free convection heat sink with good airflow may be adequate to cool a CMOS sensor. However, this passive thermal solution may not suffice for outdoor applications. Active cooling with a Peltier cooling solution is the only option here.

Condition Based Monitoring and MEMS Sensors

Lately, there has been a tremendous improvement in MEMS accelerometer performance. So much so, it can now compete with piezo vibration sensors that are all-pervasive. This is because MEMS sensors offer several advantages including smaller size, lower power consumption, low noise levels, wider bandwidth, and a higher level of integration. Consequently, the industry is now increasingly using MEMS sensors in CbM or condition-based monitoring for facility and maintenance. Engineers find CbM very useful, as it helps in detecting, diagnosing, predicting, and ultimately, avoiding faults in their machines.

The smaller size and ultra-low power consumption of MEMS accelerometers allow for replacing wired piezo sensors which are typically bulky, with wireless solutions. Moreover, it is easy to replace bulky single-axis piezo sensors with small, light, and triaxial MEMS accelerometers. The industry finds such replacements cost-effective for continuously monitoring various machines.

The world over, millions of electric motors are in continuous operation. They account for about 45% of global electricity usage. In a survey across industries, more than 80% of the companies in the survey claimed to experience unplanned maintenance. More than 70% of the companies remain unaware that their assets are due for upgrade and maintenance. With Industry 4.0, or the IoT, the industry is moving towards digitization to improve its productivity and efficiency.

The trend is more toward wireless sensor systems. An estimate finds there will be about 5 billion wireless modules in smart manufacturing by 2030. Although most critical assets require a wired CbM system, there are many, many more that will benefit from wireless CbM solutions.

For the best performance, speed, reliability, and security, it is difficult to surpass a wired CbM system. For these reasons, greenfield sites still deploy them. However, installing wired CbM systems requires routing cables across factory floors. This may be difficult in cases where it is not possible to disturb certain machinery. Industrial wired sensor networks typically use 60 m or 200 ft of cables, which can be substantially expensive depending on the material and labor the process involves. Some deployments may also require wire harnesses and routing through existing infrastructure, thereby increasing the cost, complexity, and time to install.

On the other hand, brownfield sites may not be amenable to wired solution installations. For them, although the wireless systems may initially appear to be more expensive, other factors can lead to significant cost savings. For instance, initial cost savings can come from less cabling, fewer maintenance routes, and lower hardware requirements. Over the lifetime of the wireless CbM installation, substantial cost savings can accrue from the ease of scalability and more effortless maintenance routines.

Wireless installations depend on batteries for powering them. Depending on the level of reporting, batteries may last several years. Deployment of wireless systems based on energy-harvesting techniques can make maintenance of these systems even easier and less expensive. However, once a company decides to go wireless, they must focus on the best technology for CbM that suits their application, of which, there are quite a few to choose from, such as Bluetooth Low Energy, GlowPAN, and Zigbee.

Nanowire Sensors

The Center of Excellence at the Australian Research Council for TMOS or Transformative Meta-Optical Systems, has announced the development of a new type of sensor. This is a minuscule sensor made for detecting nitrogen dioxide. They claim it can protect the environment from pollutants that vehicles typically release. These pollutants can cause acid rain and lung cancer.

According to the researchers, the sensor consists of an array of nanowires. The array occupies a square of only a fifth of a millimeter on each side. That means a silicon chip can easily incorporate the sensor.

The researchers have published their findings in the latest issue of Advanced Materials. They have described their sensor as not requiring any power source, as it has a built-in solar-powered generator to run it.

According to the researchers, by incorporating the new sensor into a network benefits the Internet of Things technology, as the sensor has low power consumption, low system size, and is inexpensive. They claim that it is possible to install the sensor into a vehicle. If the sensor were to detect dangerous levels of nitrogen dioxide from exhaust emissions, it will sound an alarm and send an alert to the owner’s phone.

The researchers feel this device is only a beginning, as they can adapt the sensor for the detection of other gases like acetone, which can lead to the design of a ketosis breath tester. Such a non-invasive tester can help to detect diabetic ketosis, saving countless lives.

This is an important development, as existing detectors require a trained operator and are bulky and slow. The new device, in contrast, detects gases instantly, measuring less than one part per billion of the gas. The prototype from TMOS even has a USB interface, allowing it to connect to a computer.

Belonging to the NOx category of pollutants, Nitrogen dioxide is highly dangerous to humans even when present in very small concentrations. Moreover, it contributes to acid rain, cars generate it commonly as a pollutant, and gas stoves can also generate it indoors.

Common to the fundamental construction of a solar cell, the nanowire sensor also consists of a PN junction, but in the shape of a nanowire. Sitting on a base, the nanowire is a small hexagonal pillar that has a diameter of about 100 nanometers. The complete sensor has a thousand of these nanowires in an ordered array, with the spacing between them measuring 600 nanometers.

Made from Indium Phosphide, the sensor has its base doped with zinc, forming the P part, while the tip of the nanowires forms the N section, as the researchers have doped it with silicon. Separating the P and N sections, the middle part of each of the nanowires remains undoped, constituting the intrinsic section.

As in the case of a solar cell, any light falling on the device causes the flow of a small current between the N and P sections. If nitrogen dioxide is present and touches the intrinsic middle section, there will be a dip in the current. This is due to nitrogen dioxide being a strong oxidizer that removes electrons.

New Graphene Sensors

While more advanced technology sectors have been late in adopting graphene, it finds plenty of interest in both lower- and high-tech applications. One of these applications is sensors based on graphene. Different industry sectors have steadily been using these sensors.

This is because graphene can be the basis of an effective sensing platform. Several interesting applications manifest this in many ways. Of these, the biosensor subsector is especially notable in attracting heavy investment. This trend is likely to continue even beyond 2022.

With graphene properties being exhaustively documented, many are now aware that they can do a lot with graphene and that many applications can benefit from its properties. Although many of these aspects are often subject to some hype, the fundamental properties of graphene make it a superior material of choice. This is primarily of account of graphene being suitable as an active sensing surface in many sensing applications.

The major advantage of graphene is its inherent thinness. This allows sensing devices made from graphene to be far more flexible and smaller in comparison to many other materials. In addition, graphene forms a very high-end active surface area.

In applications involving sensing, a high surface area is beneficial as it allows interaction with a larger range of molecules like different gases, water, biomolecules, and many other molecular stimuli. With graphene being an active surface, it is possible to attach a number of different molecular receptors and molecules to a sheet of graphene. This helps to create sensors that can detect specific molecules.

However, graphene has more advantages. Because of the high electrical conductivity of graphene, its high charge transfer properties, and high charge carrier mobility, sensors made from graphene exhibit very high sensitivity. That means, graphene sensors will generate a detectable response even from a small interaction with the environment. This happens because the excellent properties of graphene help in changing the resistivity across the graphene sheet with each small interaction. Therefore, graphene sensor help to detect even the smallest amounts of stimuli from the environment.

Because of their innate thinness, it is possible to make graphene-based sensors in small form factors, while retaining their highly sensitive sensing characteristics. It is also possible to tailor the sensors chemically for detecting a range of stimuli from the environment. This characteristic has led to the generation of much commercial interest in developing various graphene-based sensors for a variety of commercial markets involving many applications.

For instance, Paragraf has a graphene-based Hall-effect sensor that can measure changes in a magnetic field using the Hall effect. Therefore, this has increased the possibility of adding many new and interesting application areas to those that graphene sensors had not ventured into so far.

In the past year, Paragraf has demonstrated that Hall-effect sensors based on graphene are highly sensitive. They can measure currents flowing in batteries within electric vehicles for monitoring their status. Paragraf makes these sensors by depositing single layers of contamination-free graphene directly on a wafer. They repeat this following standard semiconductor manufacturing processes. This has allowed them to make several volume applications possible now, including those for fast and sensitive biosensors for detecting biomarkers within liquid samples.

Haptic Skin Sensors

Although great technological advances are taking place to engage our eyes and ears in the virtual worlds, engaging other senses like touch is a different ballgame altogether. At City University in Hong Kong, engineers have developed a wearable, thin electronic skin called WeTac. It offers tactile feedback in AR and VR.

At present, there are several wearable devices with designs that allow users to manipulate virtual objects while receiving haptic feedback from them. However, not only are these devices heavy and big but also require tangles of wire and complex setups.

In contrast, the WeTac system is one of the neatest arrangements among all others. The engineers have made it from a rubbery hydrogel that makes it stick to the palm and on the front of the fingers. The device connects to a small battery and has a Bluetooth communications system that sits on the forearm in a 5-square-centimeter patch. The user can recharge the battery wirelessly.

The hydrogel has 32 electrodes embedded in it. The electrodes are spread out all over the palm, the thumb, and the fingers. The system sends electrical currents through these electrodes to produce tactile sensations.

According to the WeTac team, they can stimulate a specific combination of these electrodes at varying strengths. This allows them to simulate a wide range of experiences. They have demonstrated this by simulating catching a tennis ball or generating the feel of a virtual mouse moving across the hand. They claim they can ramp up the sensation to uncomfortable levels, but not to the extent of making them painful. This can give negative feedback, such as a reaction to touching a digital cactus.

According to the researchers, they can pair the system up with either augmented or virtual reality. They can thus simulate some intriguing use cases. For instance, it is possible to feel the rhythm of slicing through VR blocks in Beat Saber, or catch Pokemon while petting a Pikachu in the park in AR.

Using the WeTac system, it may be possible to control robots remotely or transmit to the human operator the tactile sensations of the robot as it grips something.

Syntouch has a new tactile sensor that performs three important functions. First, it measures the impedance using a flexible bladder placed against an array of sensing electrodes fixed in a rigid core. This arrangement helps to measure deformity, somewhat like the human finger, using its ductile skin and flesh against the rigid bone structure inside it. The finger uses its fingernails to cause bulges in the skin for detecting shear forces.

Second, the tactile sensor registers micro-vibrations using a pressure sensor that the sensor core has mounted on its inside. This enables measurements of surface texture and roughness. The fingerprints are very crucial here, as they can interact with the texture.

Third, the sensor has a thermistor. Its electrical resistance is a function of temperature. Just like the human finger can sense heat, the sensor also generates heat, while the thermistor allows it to detect how it exchanges this heat when the finger touches an object.

Precision RH&T Probe Using Chilled Mirror

The Aosong Electronic Co. Ltd, with a registered trademark ASAIR, is a leading designer and manufacturer in China of MEMS sensors. They focus on the design of sensor chips, the production of wafers, sensor modules, and system solutions. They have designed a sensor AHTT2820, which is a precision relative humidity and temperature probe.

ASAIR has based the design of AHTT2820 on the principles of a cold optical mirror. It directly measures humidity and temperature. Contrary to other methods of indirect measurements of humidity through resistance and capacitance changes, AHTT2820 uses the principles of a cold optical mirror. It can directly measure the surrounding humidity. It is an accurate, intuitive, and reliable sensor.

ASAIR uses a unique semiconductor process to treat the mirror surface of this high-precision humidity and temperature sensor. It uses platinum resistance to measure the temperature by sensing the change in the resistance due to a change in temperature. This gives the high-precision humidity and temperature sensor long-term stability, reliability, and high accuracy of measurement. The sensor features a fast response speed, a short warm-up time, and an automatic balance system.

Users can connect the sensor to their computer through a standard Modbus RTU communication system. It can record data, display the data, and chart curves. The precision RH&T probe provides direct measurement of temperature and dew point. Powered by USB, the split probe is suitable for various scenarios.

The AHTT2820 is a chilled mirror dew point meter that directly measures the dew point according to the definition of dew point. Various industries widely use it. They include food and medicine production industries, the measurement and testing industry, universities, the power electronics industry, scientific research institutes, the meteorological environment, and many others.

The probe uses its optical components to detect the thickness of frost or dew on the mirror surface. It uses the detection information for controlling the temperature of the mirror surface for maintaining a constant thickness of dew or frost. It uses a light-emitting diode to generate an incident beam of constant intensity to illuminate the mirror. On the opposite side, the probe has a photodiode for measuring the reflected intensity of the incident beam from the light-emitting diode.

The probe uses the output of the photodiode for controlling the semiconductor refrigeration stack. Depending on the output of the photodiode, the system either heats up or cools down the semiconductor refrigeration stack. This helps to maintain the condensation thickness of moisture on the surface of the mirror.

As it reaches the equilibrium point, the rate of evaporation from the mirror surface equals the rate of condensation. At this time, the platinum resistance thermometer embedded in the mirror measures the temperature of the mirror, and this represents the dew point.

Under standard atmospheric pressure, it is possible to obtain the related values of absolute humidity, relative humidity, water activity, and humid air enthalpy through calculation after measuring the ambient temperature.

The probe can measure temperatures from -40 to +80 °C, with an accuracy of ±0.1 °C. It measures humidity from 4.5 to 100%RH at 20 °C, with an accuracy of ±1%RH at <90%RH.

RNC Sensors for Automobiles

With changing vehicle technology, the expectations of drivers and passengers are also undergoing a sea change. They expect a quieter in-cabin atmosphere and an escape from the noise and pollution from the road. Road Noise Cancellation or RNC sensors from Molex offer a new experience for both automotive manufacturers and users. These sensors are lightweight, inexpensive, and use an innovative compact technique of combating road noise.

With growing environmental concerns, electric and hybrid vehicles are causing a greater impact on the automotive market. As these vehicles are quieter than their counterparts with combustion engines, their occupants indicate they perceive a higher level of road noise. The road surface transmits a low-frequency broadband sound that creates a hypnotic humming road noise, through the tires, the suspension, and various body components, into the vehicle. The absence of a combustion engine makes the road noise more perceptible in electric vehicles.

Reducing this noise using sound-dampening materials can be expensive and add to the vehicle’s weight. Early attempts to cancel the road noise actively used complex wire harnesses, while the material they used was less efficient and not as economical as users desire. Moreover, sensors and sound-dampening systems in automotive applications are vulnerable to several harsh environmental factors, including dust, rocks, and water, which can easily damage them.

RNC sensors from Molex are pioneering a newer trend in the luxury category of electric vehicles. The sensing element utilizes the A2B technology that captures sound waves. The system reduces noise from the road that a combustion engine would typically mask.

The A2B audio bus technology minimizes the time the sensors take between receiving the excitation vibrations and generating the processing signal. That means noise cancellation is more efficient. In addition, the sensors can measure the road noise at a slower speed, which allows placing them farther away from the source of the sound. The technology also provides more network data channels.

RNC sensors typically capture sound waves from the vibrations of the vehicle chassis. After detecting the sound waves, it transfers them to the processing unit. This generates a cancellation wave and transmits it to the inside of the vehicle as it travels on the road. The sensors use the A2B audio bus technology by Analog Devices and are daisy-chained to each other. This has the advantage of eliminating the home-run wire harnessing or star-pattern wiring and the use of sound-dampening materials that earlier systems used.

Moles has designed the casings for the sensors to anticipate the dust and water of the harsh automotive environment, for which they carry an IP6K9K rating for the enclosure for protecting the system. Molex also offers their space-saving sealed Mini50 Connector interface. They also offer various mechanical housing configurations for orienting the sensing element to mount them perpendicular to or parallel to the ground. This allows the use of a variety of terminal sizes and connector orientations.

RNC sensors are a low-cost technology for capturing vibration energy from vehicle suspension for optimal cancellation, compared to other noise-cancellation systems. It is possible to configure them in groups of 4 to 8 sensors, depending on the need.

MEMS Vibration Sensor

Analog Devices Inc. has unveiled their MEMS or Micro-Electro-Mechanical System-based accelerometer technology at the Sensors + Test Conference in Nuremberg, Germany. The MEMS vibration sensor can track vibrations at frequencies of 22 kHz. This is especially helpful for sensing high-frequency vibrations in industrial equipment.

The MEMS technology from Analog Devices is unique in the sense that it uses two MEMS mechanisms placed beside each other. The arrangement helps to cancel out common mode noise, favoring only the differential mode noise. Vibration and shock sensors from ADI are small format sensors that enable equipment designers to build vibration-detection chips within devices for industrial process-control, rather than as add-on modules.

Most vibration sensors today are piezo-electric-based modules. They have two disadvantages—it is not possible to mass-produce them, and their range is limited to 5-kHz frequencies. On the other hand, ADI makes their accelerometers in CMOS processing lines, and they can mass produce them easily. Additionally, ADI can undercut the prices of piezo-based vibration sensors by about 50 percent. For instance, the prices of ADI vibration sensors are around $35 as opposed to piezo-based sensors at $70.

With manufacturers looking for whatever they can get for improving the production and efficiency of their equipment, MEMS vibration sensors from ADI are the right products in the right place and at the right time. Although, when comparing unit shipments, the industrial market is small compared to the consumer electronics market, revenue-wise, the former is incredibly important and offers better margins. MEMS sensors address identified needs within the industrial market sector, and therefore, provide tangible value.

In the case of piezo-based vibration sensor modules, the standard practice is to bolt them onto the side of vibrating industrial equipment. However, using the chip-based accelerometer sensor from ADI is simpler, as it is possible to integrate it right within the circuit board of the device when assembling. ADI is of the opinion that some piezo-based vibration sensor manufacturers may retrofit MEMS chips into their bolt-on modules. However, ADI also expects OEMs of industrial equipment to stop using modules and rather start integrating ADI MEMS chips directly into their pumps, motors, gearboxes, and other pieces of industrial equipment.

Industrial equipment manufacturers are increasingly using vibration sensors as these can sense on-coming failure before it happens. For instance, a deteriorating bearing will vibrate at high frequencies before it fails. As it nears failure, its vibrating frequencies will drop until it finally disintegrates totally, possibly causing damage to the rotor. This is why predictive maintenance is increasingly becoming popular.

The present trend in the industry is to move towards predictive maintenance from preventive maintenance. Early detection through predictive maintenance can cut down repair costs by as much as 25 percent. Waiting to repair equipment until something fails can push up the maintenance costs more than ten times. Compared to other predictive maintenance techniques such as ultrasonic analysis or infrared thermography, vibration analysis offers better return-on-investments, by as much as three times.

ADI offers its vibration and shock sensors in ceramic packages, available in 70g, 250g, and 500g ranges.