What is Pressure sensor accuracy

Pressure sensor accuracy is typically specified by manufacturers as a percentage of the full-scale output or a specific error value, such as ±0.25% of full-scale or ±0.5 psi. Higher-accuracy sensors may have accuracy ratings of ±0.1% or better, while lower-cost sensors may have larger error margins.

It’s important to select a pressure sensor with an accuracy level that meets the requirements of the application.

In critical applications where precise measurements are essential, higher-accuracy sensors may be necessary, while less demanding applications may tolerate lower accuracy levels.

Accuracy has a price

The cost of a pressure sensor is a function of its accuracy, the more accurate the sensor the more expensive it will be. From a manufacturing point of view, the wrong sensors can cause expensive quality or efficiency problems. That is why it is important to understand how manufactures calculate accuracy and recognize what parameters to look at when comparing pressure sensors.

By understanding how manufactures calculate accuracy, you will be able to make a more informed decision when evaluating pressure sensors. Ensuring the next sensor you select will have the required accuracy at right price for application.

What is accuracy? The International Electrotechnical Commission’s (IEC) definition of accuracy is the maximum positive and negative deviation from the specified characteristic curve observed in testing a device under specified conditions and by a specified procedure.

Unfortunately when it comes to defining accuracy for a pressure sensor it’s more complicated. Accuracy has a large effect on the cost of a pressure sensor or even more important, the quality or efficiency of the process it is measuring. It is important to understand what factors determine accuracy and what questions to ask when selecting a sensor.

Accuracy must include Hysteresis, Non-Repeatability and Non-Linearity. Non-Repeatability and Hysteresis are well defined. Hysteresis is the maximum difference in sensor output at a pressure when that pressure is first approached with pressure increasing and then approached with pressure decreasing during a full span pressure cycle. Non-Repeatability is the maximum difference in output when the same pressure is applied, consecutively, under the same conditions and approaching from the same direction.

The term “Accuracy” exists only in the users’ language. It is not defined in any standard. Nevertheless, it can be found in many data sheets for sensors. Unfortunately, there is no common idea of what accuracy means. There is not ”one accuracy“ but a large number of different specifications with regard to accuracy, all of them together describe the “accuracy” of a device.

Stability

The accuracy given in data sheets usually describes the condition of a device at the end of the production process. The device can already be exposed to environmental conditions affecting its accuracy negatively from the moment of leaving the manufacturer’s company or warehouse or during transport. It is not important how accurate the device is or if it is of a very high quality, every device changes its accuracy during its service life. This change is called long-term drift or long-term stability.

The dimension of this drift is largely influenced by the operating conditions, i.e. pressures, temperatures and other influences to which the device is exposed. In many cases, stability has a larger influence on the overall deviation than e.g. non-linearity.

Values twice or three times as high are not unusual. Stability data stated by the manufacturer can hardly be compared. Different standards describe very different tests for determining stability.

Furthermore, none of these tests is an actual copy of the real conditions of use. This is not possible because the conditions vary too much from application to application.

Consequently, stability data are only valid for uses in laboratories or under reference conditions. However, even if used under reference conditions, it is almost impossible to obtain comparable data. You cannot make time go faster. And all attempts to simulate a time lapse effect by means of thermal shocks and other methods are just attempts.

In Practice

Hysteresis and non-repeatability are pretty much the only errors you have to deal with. All other errors can be minimized or even eliminated with some kind of effort. This works easiest and clearest using the offset error.

The user can read the offset error hassle-free in unpressurised condition and enter it as offset in the corresponding evaluation instrument. In order to eliminate the span error, the pressure must be regulated exactly at full scale value. This is often not possible as there is no reference value for the pressure. In order to make the pressure sensor not to measure worse than before, the reference pressure should be three times more accurate than the intended accuracy.

Most manufacturers recommend calibrating the pressure sensors once a year, to control whether they still meet their specifications. The device is not readjusted but the actual change, i.e. the drift, is analyzed. If the drift is higher than the value specified by the manufacturer, this might be an indication for a defective device. The higher the instability, the more probability that the sensor is defective. In this case, process reliability can no longer be guaranteed if the device is still being used.

This check does not require much effort. Often it is sufficient to check if the zero point of the unpressurised device has changed. If the device can neither be checked in the system nor dismounted for examination, you should at least set a high value on a very good stability and respect it in your accuracy specifications. Unfortunately, these are not the only possible sources of error. Vibrations, electromagnetic interferences, mounting position of the sensor, power supply and even the load of the evaluation instrument might affect the accuracy of your pressure sensor. Therefore, individual consulting by a specialist is recommended in many cases.

In a nutshell

Do you know the exact accuracy of your sensor? Is it as good as you have expected? Or is it too good? You are the only person to decide which errors are relevant for you and which are not. The manufacturers’ application consultants explain which product characteristics are important for it and how they can be implemented in your application.

This ensures that you reach your targets with optimum input.

We would be well area of which is the accuracy you presently have and which is the one you actually need.

Additional Posts which may be of interest

• Basic Knowledge You Need to Know about Pressure Gauge
• How to select Pressure Gauge?
• Pressure Switch V.S Pressure Transducer, what’s the difference?
• What is The Difference between Pressure Transducer and Pressure Transmitter?
• Pressure Sensor Technology Comparison
• 10 practices need to considerate before choosing pressure transducer
• What’s the role of smart sensors in Industry 4.0?
• How sensor has been rocking our world?

In terms of pressure sensor technology, all pressure pressure transducers operate on the principle of converting a pressure change into a mechanical displacement, or deformation.

Deformation of the sensing element is then converted into an electrical signal that is processed by the measuring system. Types of pressure transducers available in the field, either individually or in combination, are mechanical, capacitance, strain gauge piezoresistive, Piezoelectric, thin- film and quartz gauge.

This article discusses how each of these types of pressure transducers operates and what are their advantage and disadvantage

Pressure Sensor Technology of Bourdon tube

Mechanical methods of measuring pressure have been known for centuries. The first pressure gauges used flexible elements as sensors. As pressure changed, the flexible element moved, and this motion was used to rotate a pointer in front of a dial.

In these mechanical pressure sensors, a Bourdon tube, a diaphragm, or a bellows element detected the process pressure and caused a corresponding movement.

A bourdon tube is C-shaped and has an oval cross-section with one end of the tube connected to the process pressure. The other end is sealed and connected to the pointer or transmitter mechanism.

To increase their sensitivity, Bourdon tube elements can be extended into spirals or helical coils. This increases their effective angular length and, therefore, increases the movement at their tip, which in turn increases the resolution of the transducer (Figliola and Beasley, 1991).

Designs in the family of flexible pressure sensor elements also include the bellows and the diaphragms,

The diaphragms are popular because they require less space and because the motion (or force) they produce is sufficient for operating electronic transducers. They also are available in a wide range of materials for corrosive service applications (Omegadyne, 1996).

After the 1920s, automatic control systems evolved in industry, and by the 1950s pressure transmitters and centralized control rooms were commonplace. Therefore, the free end of a Bourdon tube (bellows or diaphragm) no longer had to be connected to a local pointer, but served to convert a process pressure into a transmitted (electrical or pneumatic) signal.

At first, the mechanical linkage was connected to a pneumatic pressure transmitter, which usually generated a 3-15 psig output signal for transmission over distances of several hundred feet, or even farther with booster repeaters (Omega, 1996).

Later, as solid-state electronics matured and transmission distances increased, pressure transmitters became electronic. The early designs generated dc voltage outputs:10-50 mV, 0-100 mV, 1-5 V (Omega, 2003), but later were standardized as 4-20 mA dc current output signals.

However Gauges with bourdon tubes are still the most common pressure measuring devices used today. They combine a high grade of measuring technology, simple operation, ruggedness and flexibility with the advantages of industrial and cost-effective production. Needing no external power supply, bourdon tube gauges are the best choice for most applications.

In Eastsensor, we have been produced some types of mechanical pressure gauge with Bourdon tube technology to serve our customers measuring processes in many application, please check our product out below.

• ESG501 Economical Pressure Gauge
• ESG502 Shock Resistance Oil Pressure Gauge
• ESG503 Stainless Steel Bourdon Tube Pressure Gauge

Pressure Sensor Technology of Strain gauge

The first unbonded-wire strain gauges were introduced in the late 1930s. In this device, the wire filament is attached to a structure under strain, and the resistance in the strained wire is measured. This design was inherently unstable and could not maintain calibration.

There also were problems with degradation of the bond between the wire filament and the diaphragm, and with hysteresis caused by thermoelastic strain in the wire (Omega, 1996). The search for improved pressure and strain sensors first resulted in the introduction of bonded thin-film and finally diffused semiconductor strain gauges.

These were first developed for the automotive industry, but shortly thereafter moved into the general field of pressure measurement and transmission in all industrial and scientific applications.

Strain gauge sensors originally used a metal diaphragm with strain gauges bonded to it, the signal due to deformation of the material is small, on the order of 0.1% of the base resistance. Semiconductor strain gauge are widely used, both bonded and integrated into a silicon diaphragm, because the response to applied stress is an order of magnitude larger metallic strain gauge.

Semiconductor pressure sensors are sensitive, inexpensive, accurate, and repeatable (Omega, 2003). When a strain gauge, which is shown in, is used to measure the deflection of an elastic diaphragm or Bourdon tube, it becomes a component in a pressure transducer. Strain gauge-type pressure transducers are widely used. Strain-gauge transducers are used for narrow-span pressure and for differential pressure measurements.

Essentially, the strain gauge is used to measure the displacement of an elastic diaphragm due to a difference in pressure across the diaphragm. These devices can detect gauge pressure if the low pressure port is left open to the atmosphere, or differential pressure if connected to two process pressures. If the low pressure side is a sealed vacuum reference, the transmitter will act as an absolute pressure transmitter (Omega, 2003).

Bonded foil strain gauge, which  has excellent stability and good overpressure protection is the very good choice to make wide and big pressure range transmitter.

Pressure Sensor Technology of Capacitive

Capacitive pressure sensors use a thin diaphragm, usually metal or metal-coated quartz, as one plate of a capacitor. The diaphragm is exposed to the process pressure on one side and to a reference pressure on the other. Changes in pressure cause it to deflect 29 and change the capacitance. The change may or may not be linear with pressure and is typically a few percent of the total capacitance (Considine, 1993).

The capacitance can be monitored by using it to control the frequency of an oscillator or to vary the coupling of an AC signal through a network. The electronics for signal conditioning should be located close to the sensing element to prevent errors due to stray capacitance. The schematic of a capacitive pressure sensor is shown in below (Omega, 2003).

Pressure Sensor Technology of Piezoresistive

The piezoresistive pressure sensor elements consist of a silicon chip with an etched diaphragm and, a glass base anodically bonded to the silicon at the wafer level. The front side of the chip contains four ion-implanted resistors in a Wheatstone bridge configuration.

The resistors are located on the silicon membrane and metal paths provide electrical connections. When a pressure is applied, the membrane deflects, the piezoresistors change unbalancing the bridge.

Then a voltage develops proportional to the applied pressure (Sugiyama et al., 1983). Silicon piezoresitive sensors have been widely used for industrial and biomedical electronics (Ko, et al., 1979). The piezoresitive sensors have excellent electrical and mechanical stability that can be fabricated in a very small size.

Characteristics comparison between Capacitive and Piezoresistive

The pressure to capacitance difference relationship for three devices with various sizes in diaphragm and electrode areas is shown below, where Dia. represents the diaphragm diameter and EAR represents the ratio of electrode area to diaphragm area.

Comparing the experimental and simulation results, the deviations could be attributed to process variations in diaphragm dimensions. Extracting the sensitivity of the devices with least square fit, the errors are within 10%.

Comparing our device with a commercially available piezoresistive pressure sensor which has similar operating range, the preliminary result shows that when both sensors are not temperature compensated and for the temperature range we tested, the temperature coefficient of sensitivity of our capacitive device is 10 times better than the piezoresistive pressure sensor.

Advantage of Capacitive Sensing

Capacitance is a measure of energy stored between two conducting plates or electrodes holding an opposite charge.

Capacitance varies according to the strength of the charge, the distance between electrode plates, and the size of the plates. By keeping the charge between capacitor plates constant, you can tell how far one plate is from another by measuring the voltage between them.

Increase fluid pressure deflects the diaphragm (electrode plate), either closing or increasing the distance to the other plate, which changes the charge between plates. This simple approach proves both accurate and reliable, and offers many benefits over measuring pressure with strain gauges.

Advantage:

• Stable:  Capacitive sensor/transmitter does not rely on an intermediate element, such as a strain gauge, to produce an output. They are also simpler and more reliable than bonded strain gauge elements because they require no adhesives, which can produce self-imposed strain from differential thermal expansion.

• Good compatibility: Media compatibility problems of integrated strain gauge transducers are avoided in capacitive transducers because the sensing diaphragm (electrode plate) can be constructed of stainless steel, ceramics, or other chemically non-reactive materials. They also accommodate a wide range of temperatures.

• Less error & high accuracy: Capacitive elements also produce a stronger output than strain gauge elements. Some signal conditioning is still required, but requires less amplification. Less amplification means error becomes a smaller portion of the output signal. Ultimately, accuracy is improved.

• EMI&RFI immune: EMI and RFI can generate stray fields, introducing electrical signals that controls may “confuse” with the actual transducer output. Unlike  strain gauge elements, the high level output signal produced by capacitive type sensing elements is insensitive to low or moderate EMI and RFI, maintaining the integrity of the output.

• Reliability for millions cycles: Capacitive-sensing elements can also withstand millions of full scale pressure cycles without affecting accuracy because they do not suffer the same effects caused by the use of adhesives.

Performance of pressure sensing devices is affected by their design and technology. When compared to strain gauge sensors, capacitive sensors produce highly accurate, stable, EMI/RFI immune pressure transducers that meet performance requirements.

Disadvantage of Strain Gauge Sensing

Strain gauges are widely used to measure, electrically, how much a material shrinks or stretches in response to an applied force, torque, or stress. Strain gauge pressure-sensing elements use a diaphragm combined with a strain gauge to generate an output signal representative of the fluid pressure.

Disadvantage:

• Accuracy degradation: Bonded strain gauge sensing elements use an adhesive to attach the strain gauge to the diaphragm. Problems arise with this design because the adhesive often has a coefficient of thermal expansion different from the diaphragm and strain gauge.

• So if pressure remains constant, but temperature changes dramatically, the adhesive may expand or contract more than the diaphragm. The differential expansion could impose a strain on the strain gauge that would produce a different output signal even through the pressure did not change at all. Over time, this self-induced strain can permanently degrade accuracy.

• No rugged structure: Furthermore, millions of expansion and contraction cycles can weaken the adhesive bond. In most cases, this deteriorates accuracy, but in extreme cases–especially when aggravated by heavy vibration–the bond can fail completely, rendering the transducer useless.

• Incompatibility with adhesives: Integrated strain gauge sensing elements are designed with the strain gauge embedded in a diaphragm made of silicone or other material. While they avoid adhesives–and the problems associated with them– integrated strain gauge sensing elements compromise the fluid compatibility common with stainless steel diaphragms.

• Vulnerability: Diaphragms of silicone and other materials are attacked by a wide variety of chemicals found in industrial fluids. They also accommodate a narrower range of temperatures. Even if chemical incompatibility does not cause transducer failure, it can change the physical properties of the diaphragm, which degrades accuracy.

• EMI&RFI problem: Both types of strain gauges sensing elements produce relatively weak output signals. This means that weak or moderate EMI and RFI can degrade output.

Advantage of Piezoresistive pressure sensors

Piezoresistive based transducers rely on the piezoresistive effect which occurs when the electrical resistance of a material changes in response to applied mechanical strain.

In metals, this effect is realized when the change in geometry with applied mechanical strain results in a small increase or decrease in the resistance of the metal. The piezoresistive effect in silicon is due primarily to changes at the atomic level and is approximately two orders of magnitude larger than in metals.

As stress is applied, the average effective mass of the carriers in the silicon either increases or decreases (depending on the direction of the stress, the crystallographic orientation, and the direction of current flow).

This change alters the silicon’s carrier mobility and hence its resistivity. When piezoresistors are placed in a Wheatstone bridge configuration and attached to a pressure-sensitive diaphragm, a change in resistance is converted to a voltage output which is proportional to the applied pressure.

The piezoresistive pressure sensor also called Solid State Pressure Sensor, have excellent electrical and mechanical stability that can be fabricated in a very small size.

Advantage:

• Can eliminate the case-mounting effects on bias: Due to the small size of the pressure sensing silicon sensor, piezoresistive transducers may be constructed in a variety of packaging options that have been designed to eliminate the case-mounting effects on bias and sensitivity as well as low-frequency output generated by thermal expansion following proper installation. Piezoresistive SOI Sensors are fully integrated, monolithic structures.

• Smaller size can do more jobs: The final form factor of a transducer is one of the more important device attributes for many customers. piezoresistive sensor technology offer more flexibility in packaging than any other technology due to the extremely small size of the sensing element. Automotive applications include engine air, oil, cooling and fuel systems, brake systems, transmissions and general laboratory/developmental pressure measurements.

• Typical aerospace applications are scale-model and full-scale flight tests. Scale-model wind tunnel test articles, for instance, require the measurement of pressures on leading edge portions of the airframe where the radius can be under one tenth of an inch. In other applications, pressure measurements must be made in areas where the test article thickness is very thin and cannot be penetrated. Only piezoresistive pressure transducers may be manufactured to small enough sizes to support either of these installations.

• Extreme Environments Operability/Ruggedness: A majority of harsh environment commercial applications always use piezoresistive pressure transducers due to the small sensing element size (≈ 0.25 x 10-6 inch3 in volume), miniscule mass and robust construction.
• Piezoresistive pressure transducers do not require external amplifiers and special cables that other technologies need. Piezoresistive pressure transducers operate well in aircraft engine, nuclear, downhole, cryogenic, space, motor sports, and other extreme environment pressure measuring applications.
• Good temperature compensation ability: piezoresistive pressure sensors may be conditioned by the use of embedded digitally-programmed electronics. The programmable analog sensor conditioner circuitry is paired with sufficient memory to linearize the piezoresistive pressure sensor to better than ±0.1% of full scale at a constant temperature.

• Since the bridge resistance changes predictably temperature and piezoresistive pressure sensors are extremely repeatable, the embedded electronics may also be used to correct for bias and sensitivity shifts due to temperature. Piezoresistive pressure transducer temperature sensitivity may be controlled to within ±0.001% of full scale per degree Fahrenheit after electronic characterization of thepressure sensor is programmed into the embedded conditioning electronics

• Cost competitive: Installation costs of measurement systems dedicated to piezoresistive pressure transducers are generally lower than systems designed for piezoelectric pressure transducers. Transducers, cabling, and electronics for piezoresistive pressure transducers are each less than the cost of the corresponding piezoelectric pressure transducer system component. Fewer individual components are also a characteristic of piezoresistive pressure transducer installations.

Disadvantage of Piezoelectric-based sensing

Piezoelectric-based transducers rely on the piezoelectric effect, which occurs when a crystal reorients under stress forming an internal polarization. This polarization results in the generation of charge on the crystal face that is proportional to the applied stress2. Quartz, tourmaline, and several other naturally occurring crystals exhibit a piezoelectric effect.

An electric charge proportional to the applied force is generated when a piezoelectric material is stressed by being coupled to an appropriate forcesumming device. Specially formulated ceramics can be artificially polarized to be piezoelectric with sensitivities 100 or more times higher than found in natural crystals3.

Unlike strain gage sensors, piezoelectric sensors require no external excitation. These sensors exhibit high output impedance and low signal levels; therefore, piezoelectric devices require the use of special equipment such as low-noise coaxial cable and charge amplifiers in the measurement chain.

Disadvantage:

• Susceptibility and inability: The high degree of stiffness provided by the compression mode enables the measurement of relatively high frequencies, but this construction worsens low frequency response due to thermally induced errors. Additionally, the compression mode construction is susceptible to a form of zero shift. Failure of the preload screw to maintain a constant force between the mass and the element will result in an output error. An abrupt change in the preload force may not be a one-time event and the resulting level shifts will be impossible to discern from pressure data.

• Construction limitation: Pressure transducers constructed using the compression mode can also be quite sensitive to installation. Virtually all miniature piezoelectric pressure transducers are constructed within a threaded assembly or a case requiring a threaded mounting adapter.
• If excessive torque is applied during transducer installation or if the sealing surface is improperly machined, the body of the sensor may become distorted and the sensitivity of the device will be affected. All piezoelectric pressure sensors are susceptible to some degree of degraded performance as a result of excessive mounting torque. The user is expected take special precautions to apply the manufacturer-recommended torque during installation.

• Big size if compare to piezoresistive technology: The smallest commercially available piezoelectric pressure transducer is 0.9 inches in length, 0.19 inches in diameter, and has an active sensing region 0.099 inches in diameter. However some isolated piezoresistive pressure transducer can be 0.375 inches in length, 0.055 inches in diameter, and having an active sensing element that is approximately 0.035” x 0.035”. This means that the smallest piezoresistive sensor is an order of magnitude smaller in volume, weight and sensing area than piezoelectric pressure sensor.

• Invalid to absolute pressure measurement: Piezoelectric pressure transducers are incapable of absolute pressure measurement. Users may therefore be unaware they are operating in a region outside the recommended pressure range. For all pressure transducers, it is best to limit dynamic pressure to frequencies of 30% of resonance frequency. Approaching the diaphragm resonant frequency will result in erroneous data and may lead to diaphragm failure.

• Accuracy decline in extreme temperature: All piezoelectric pressure transducers exhibit decreased insulation resistance when exposed to elevated temperature. This effect is due in part to the piezoelectric element, but the mineral insulated cable necessary to withstand the high temperatures typically contributes the largest error source. Specially constructed charge amplifiers must be used that are designed to operate with low impedance systems. These instruments capacitively couple the charge amplifier to the transducer/cable system to minimize the impact of potentially large offset voltages.

Features of Sputter deposited thin-film sensor

Sputter deposited thin film pressure sensor is a kind of Piezoresistive pressure sensors, difference exist that the thin-film sensor consists of a resistor pattern that is vaporized or sputter-deposited  onto the force-summing element (the measuring diaphragm). In some transducers the resistors are not directly mounted on the diaphragm but are on a beam linked to the diaphragm by a push rod.

Many applications use a manufacturing process known as thin-film sputtering deposition. The typical sputtering process uses an ion beam to impact the surface of a sputter material such as gold, silver, or other metal or metallic oxide. In so doing, some of the sputter-material atoms get knocked into free space. The atoms bond with a substrate material to form a thin coating that may be only a few atoms thick.

• Integrity & Ruggedness: In the area of MEMS sensors, the sputtering-deposition technique lets manufacturers form sensors directly on the stressed substrate. The sensor becomes an integral part of the assembly, instead of being bonded to the stressed surface as are foil, resistive, and silicon strain gages. Combined with a Wheatstone bridge, thin-film sputtering-deposition strain gages eliminate many of the problems seen with these other measuring techniques, such as bonding separation or creep.

• Sandwiched structure: Almost any material can be used as a substrate for the sensor including stainless steel, Inconel, Hastaloy, aluminium, sapphire, and titanium. The process begins by preparing the surface of the substrate with diamond slurry to remove all surface pinholes and cracks.
• A dielectric layer is first deposited on the substrate to insulate circuit power from the underlying metal. Then a thin film of resistive alloy is sputtered over the dielectric layer. This layer is laser trimmed under power to produce the balanced resistors of the Wheatstone bridge. Wires attached to bonding pads applied to the circuit provide power egress. An encapsulation layer coats the final assembly to protect the thin film.

• Nearly perfect performance if made by sapphire: If made by sapphire, the sapphire pressure-gauge system is vacuum-filled and the resistor pattern forms a Wheatstone bridge. This system benefits from the elastic performance of the sapphire and its stable deformation properties. The result is a sensor with good repeatability, good stability, low hysteresis, and low drift. A high-gauge factor improves the resolution over traditional designs. The main disadvantages are low output level and high cost.

Additional Posts which may be of interest

• How to select Pressure Gauge?
• Pressure Switch V.S Pressure Transducer, what’s the difference?
• What is The Difference between Pressure Transducer and Pressure Transmitter?
• Basic Knowledge You Need to Know about Pressure Gauge
• 10 practices need to considerate before choosing pressure transducer
• 5 Pressure Sensor Working Principles You Need to Know

Sensors for current world

Like the organs of human being, sensor are key instruments in securing information, and therefore, play a significant role in industrial production, defense construction and in the field of science and technology.

However, in recent years, the development of sensor, is far behind the rapid development of computer, the brain.

And automation and intelligentialize in measuring and control system are setting higher demands for sensing, which require not only higher accuracy, reliability, and stability, but also a certain abilities of data processing, self-test, self-calibration, and self-compensation.

Traditional one, which is referred as dumbsensor by some insiders, can hardly meet these requirements. It was when the smart sensing enters the market.

The research of smart sensing across the world focuses in the field of science and technology, combining the technology of microcomputer and sensing, allowing the sensor to make full use of the computing and storage capacity of computer to process the data acquired.  Generally speaking, a smart sensor features the following functions:

• Self-compensation ability
• Self-calibration function
• Self-diagnostic function
• Data-processing function
• Two-way communication function
• Information storage and memory functions
• Digital output function

Statistics show that the market size of sensor in the US in 2007 was US$235 million, and grew at a compound annual growth rate of 30% in the following years. Global Sensor Market is expected to garner $241 billion by 2022, registering a CAGR of 11.3 % during the forecast period 2016 – 2022.

Sensing element is a device that detects physical input such as light, heat, motion, moisture, pressure, or any other entity, and responds by producing an output on a display or transmits the information in electronic form for further processing. The Sensing element find their applications various industries such as electronics, IT & telecommunication, automotive and healthcare among others.

In the current scenario, smart grid, smart homes, smart water networks, intelligent transportation are infrastructure systems that connect our world are trending. These systems are assembled through the use of sensor, and the entire physical infrastructure is closely coupled with information and communication technologies.

Intelligent monitoring and management can be achieved via the usage of networked embedded systems, in which devices are interconnected to transmit useful measurement information and control instructions via distributed sensor networks.

Industry 4.0

The demand for sensor is globally expected to rise during the forecast period due to growing trend of internet of things (IoT)  and industry 4.0, advancement in consumer electronic products, increasing usage of sensor in smartphones, and robust demand in automation industry.  Moreover, surge in the automotive sector and growing demand of wearable devices open opportunities in the market.

The demand for sensor is expected to surge due to heavy investments on the R&D by many key players, including STMicroelectronics, Qualcomm Technologies, Inc., Sony Corporation, and others, leading to the improvement in sensing quality and efficiency.

For instance, in October 2016, STMicroelectronics and HMicro together launched a single-chip product HC1100 for clinical-grade, disposable smart patches and biosensor.  These smart patches and biosensor are especially designed for wired wearable devices such as vital sign monitoring and electrocardiogram.

The growing need of these devices is anticipated to fuel up the demand in overall sensor market.

Pressure Sensors

By providing accurate and reliable pressure measurements, pressure sensors have become indispensable components in a wide range of industries and applications, driving innovation, improving efficiency, and enhancing safety across various sectors. Their widespread adoption and integration have truly rocked the world, enabling advancements that have transformed countless aspects of modern life.

Automotive Industry

In modern vehicles, pressure sensors play a crucial role in monitoring tire pressure. For instance, a Tire Pressure Monitoring System (TPMS) uses pressure sensors to measure the air pressure in each tire. If the pressure falls below a certain threshold, typically around 25% below the recommended pressure, the sensor triggers a warning light on the dashboard, alerting the driver to take action. This simple yet effective system improves fuel efficiency, enhances safety, and extends tire life.

Check more details: Automobile Pressure Sensor Applications

Industrial Automation

Pressure sensors are essential in hydraulic and pneumatic systems used in factories and manufacturing plants. For example, in a hydraulic press used for metal forming, pressure sensors monitor the hydraulic fluid pressure, ensuring it remains within the optimal range (typically 2,000-5,000 psi) for efficient and safe operation. Too high pressure could lead to component failure, while too low pressure may result in insufficient force for the forming process.

Medical Devices

In respiratory therapy, pressure sensors are used in ventilators and continuous positive airway pressure (CPAP) machines to monitor and regulate the air pressure delivered to patients. For instance, in a CPAP machine, the pressure sensor maintains the air pressure between 4-20 cmH2O (centimeters of water), a range essential for keeping the airway open and improving breathing for patients with sleep apnea.

Check more details: Medical Pressure Sensor Applications

Environmental Monitoring

Weather stations rely on pressure sensors to measure atmospheric pressure, a crucial parameter for weather forecasting. For example, a barometric pressure sensor with an accuracy of ±0.3 hPa (hectopascals) can detect subtle changes in air pressure, enabling meteorologists to predict the formation and movement of weather systems accurately.

Oil and Gas Industry

Downhole pressure sensors are used in oil and gas exploration and production to measure the pressure within the well during drilling operations. These sensors can withstand extreme temperatures (up to 200°C) and pressures (up to 30,000 psi), providing critical data for optimizing drilling processes and ensuring safe operations.

Consumer Electronics

In modern smartphones and wearable devices, pressure sensors are used for altitude tracking, gesture recognition, and even blood pressure monitoring. For instance, a pressure sensor with a range of 300-1100 hPa and an accuracy of ±1 hPa can reliably measure altitude changes, enabling fitness trackers to calculate data like elevation gain during hikes or climbs.

Additional Posts which may be of interest

• What’s the role of smart sensors in Industry 4.0?
• Basic Knowledge You Need to Know about Pressure Gauge
• Pressure Switch V.S Pressure Transducer, what’s the difference?
• What is The Difference between Pressure Transducer and Pressure Transmitter?
• Pressure Sensor Technology Comparison
• 10 practices need to considerate before choosing pressure transducer