Contents of this article:

1. Working principle of pressure sensor
2. Main types and characteristics of pressure sensors
3. Application field of pressure sensor
4. How to choose the right pressure sensor
5. Installation and use guide of pressure sensor
5.1 What Should I Pay Attention to when Installing a Pressure Sensor?
5.2 What is the operating voltage range of the pressure sensor? Does the power supply affect the performance of the sensor?
6. Maintenance and maintenance of pressure sensor
6.1 What are the methods for routine maintenance of pressure sensors?
6.2 How to Perform Calibration? How long is the calibration cycle?
7. What are the common faults of pressure sensors?
8. Conclusion

Do you know how important pressure sensors are in modern industry and technology? Do you realize how these small but powerful devices have changed the way we monitor and control gas or liquid pressure? From manufacturing to aerospace, automotive engineering to healthcare, pressure sensors are everywhere, ensuring system performance and safety. And not only do they work stably in extreme environments, they also provide a highly sensitive response to meet a wide range of needs, from small pressure changes to high-pressure conditions. With the rise of the Internet of Things (IoT) and intelligent systems, pressure sensors with integrated digital interfaces and wireless communication capabilities are becoming the industry standard, further boosting the level of automation.

So, how do we properly select, install, and maintain these important components? Through this article, we will discuss the basic principle of the pressure sensor, the selection of key parameters, the matters needing attention when installing and the method of daily maintenance. In this way, we can better leverage the advantages of the pressure sensor, optimize the design, and improve the efficiency and reliability of the overall system. Are you ready to dig in? Let's get started!

1. Working principle of pressure sensor

Pressure sensors convert externally applied pressure into a measurable electrical signal through different physical principles. A common type is a strain gauge sensor, which takes advantage of the fact that a metal or semiconductor material deforms when stressed, changing its resistance value. When these materials are stretched or shortened by pressure, their internal resistance changes. By connecting to a Wheatstone bridge circuit, this resistance change can be converted into a voltage signal proportional to the pressure applied. Another type of piezoresistive sensor is based on the pressure-sensitive nature of a semiconductor material such as silicon, which changes its resistance when the material is compressed or stretched, again using a Wyeth bridge to amplify and detect this change.

Capacitive pressure sensors work by changing the distance between two parallel plates to affect the capacitance value. One plate is usually fixed, and the other is a diaphragm that can move according to the pressure. As the pressure changes, the distance between the two plates increases or decreases, and the capacitance also changes, so that the current pressure can be known by measuring the capacitance value. Piezoelectric sensors rely on the phenomenon that certain crystalline materials generate electrical charges when subjected to mechanical stress. When such materials are subjected to pressure, an electrical signal is generated that is proportional to it, making them ideal for applications that require a rapid response to dynamic pressure changes.

Piezoelectric pressure sensor working principle

The resonant pressure sensor adopts MEMS technology, based on the principle that the resonance frequency of the object varies with the shape, material and surrounding environmental conditions. The small oscillator in this type of sensor acts as a sensitive element and exhibits different vibration frequencies under different pressure conditions. By monitoring changes in this specific frequency, information about external pressures can be obtained. Each pressure sensor has its own unique advantages and scope of application, so it is necessary to consider many factors such as accuracy requirements, working environment and cost when choosing practical applications.

2. Main types and characteristics of pressure sensors

By understanding the characteristics of different types of pressure sensors and their respective advantages and disadvantages, we can choose the most suitable pressure sensor according to the specific application needs.

The following are the main types of pressure sensors and their characteristics:

Strain gauge type:

Features: Strain gauges made of metal or semiconductor materials are used to sense mechanical deformation. When the strain gauge is subjected to external force, it will produce a small resistance change.

Application: Widely used in industrial process control, automotive engineering and aerospace and other fields.

Advantages: Low cost, good stability.

Disadvantages: High temperature sensitivity, temperature compensation is required.

Piezoresistive:

Features: Based on the piezoresistive effect of semiconductor materials such as silicon, that is, the resistivity of the material changes under pressure.

Application: Suitable for high precision measurement, such as blood pressure monitoring in medical devices.

Advantages: high sensitivity, fast response speed.

Disadvantages: There is also a certain temperature dependence.

Capacitive:

Features: Pressure changes are detected by changing the distance or dielectric constant between the two conductor plates, thus affecting the capacitance value.

Application: Used in food processing, pharmaceutical industry and other places with high hygiene requirements.

Advantages: insensitive to temperature, with good linearity.

Disadvantages: Relatively high manufacturing costs.

Piezoelectric type:

Features: Using the characteristics of some crystalline materials to generate electric charge when stressed, the pressure is directly converted into electrical signals.

Applications: Suitable for dynamic stress measurement, such as vibration analysis and impact testing.

Advantages: Dynamic response is fast, self-electricity does not require external power supply.

Disadvantages: Not suitable for static pressure measurement, as no signal is generated when there is no continuous pressure applied.

Resonant type:

Features: Based on the principle that the resonance frequency of the object changes with the shape and material, it is usually achieved by MEMS technology.

Application: Used in precision instrumentation to provide extremely high resolution pressure measurement.

Advantages: Very high accuracy and long-term stability.

Disadvantages: High cost and complex design.

Fiber optic type:

Features: The use of light waves as information carriers, through optical fiber transmission, and can be detected by optical means such as interferometers to detect changes in optical path caused by pressure.

Application: Suitable for remote contactless measurement in harsh environments.

Advantages: Strong anti-electromagnetic interference ability, can work in high temperature and high pressure environment.

Disadvantages: Higher cost, more complex installation and calibration.

Ceramic pressure sensor:

Features: Using the piezoresistive effect of ceramic materials, it can withstand a large pressure range.

Application: Suitable for high-pressure environments, such as water treatment systems and hydraulic systems.

Advantages: Corrosion resistance, can work in extreme conditions.

Disadvantages: Sensitivity may not be as good as some other types of sensors.

3. Application field of pressure sensor

Pressure sensors are used in a wide range of industries and scenarios, and the following are just some examples of pressure sensor applications:

Industrial automation: Pressure sensors are used to monitor air pressure, oil pressure, water pressure, etc. in various industrial processes to help control pressure changes in pumps, valves, pipes, containers, storage tanks, and machinery. For example, in the petrochemical, power, food processing and pharmaceutical industries.

Transportation:

Automotive: Monitor engine pressure, tire pressure, brake system pressure, and airbag system pressure.

Aviation: The pressure difference between the inside and outside of the aircraft is measured to ensure flight safety.

Railways and ships: Monitor the pressure status of hydraulic systems, brake systems and other critical components.

Medical equipment: Pressure sensors are used in medical instruments such as blood pressure monitors, ventilators, infusion pumps, etc., to monitor pressure changes within the human body, such as the pressure of the heart and lungs, to support diagnosis and treatment.

Smart home and life: Installing pressure sensors on smart mattresses, seats or floor MATS can detect the presence of people and trigger the corresponding smart scene; It can also be used in consumer electronics, such as key pressure sensing in smartphones.

Environmental monitoring: Used in weather forecasting stations, air quality monitoring points and other occasions to record changes in atmospheric pressure.

Energy: Oil RIGS, gas pipelines and other facilities use pressure sensors to ensure safe and efficient operations.

Research and development: In scientific research, pressure sensors are used in laboratory tests and experiments, especially in fields such as fluid dynamics and materials science.

Agriculture: Irrigation systems utilize pressure sensors to precisely control water flow and optimize water use.

Sports and Fitness: Pressure sensors embedded in exercise equipment, such as smart sandbags, are used to evaluate the effects of strength training, or to monitor the intensity of the user's activity in a wearable device.

4. How to choose the right pressure sensor

When selecting a pressure sensor, you can follow these steps to ensure that the selected sensor meets the specific requirements of the application:

① Define the measurement requirements：

Determine the type of pressure to be measured (absolute, gauge, differential, etc.).

Understand the required measurement range, i.e. minimum and maximum working pressure.

Confirm the required pressure unit (e.g. Pa, bar, psi, kPa, etc.).

② Determine accuracy and resolution:

Determine the required measurement accuracy according to the application scenario. For example, higher accuracy may be required in precision instruments.

Resolution refers to the minimum amount of change that a sensor can detect. If you need to capture subtle changes, you need higher-resolution sensors.

③ Consider environmental factors:

Temperature range: Ensure that the sensor can operate properly within the expected operating temperature range.

Humidity, vibration, electromagnetic interference and other factors can also affect the choice of sensors.

If used outdoors or in harsh environments, check the IP protection level to ensure adequate protection.

④ Media compatibility:

Identify the medium (liquid, gas, or other) to be contacted and confirm that the sensor is compatible with that medium.

For corrosive or special chemical media, choose a sensor made of a material with corresponding resistance.

⑤ Output signal:

Decide whether you want analog output (e.g., 4-20mA, 0-5V, 0-10V) or digital output (e.g., I²C, SPI, CAN, Modbus, etc.).

Digital outputs are generally easier to integrate into modern control systems, while analog outputs are better suited to legacy systems.

⑥ Mechanical interface:

Verify that the sensor is mounted (threaded, flanged, etc.) and the physical size is suitable for the existing equipment.

If space is limited, look for a sensor with a compact design.

⑦ Power requirements:

Look at the sensor's operating voltage range and make sure it is compatible with your existing power system.

Consider power consumption, especially in battery-powered applications.

⑧ Certification and compliance:

Check whether there are relevant industry standards or regulatory requirements, such as CE, UL, ATEX explosion-proof certification.

In some cases, such as in the medical or food processing sectors, additional hygiene or safety standards need to be met.

⑨ Cost-benefit analysis:

Find the best value for money within your budget.

Consider factors such as long-term maintenance costs, longevity and after-sales service.

By carefully evaluating the above aspects and combining them with specific application scenarios, we believe that you can more accurately select the pressure sensor that best meets your needs.

5. Installation and use guide of pressure sensor

5.1 What Should I Pay Attention to when Installing a Pressure Sensor?

Before installing a pressure sensor, the first task is to select a suitable location. This location should facilitate routine maintenance and regular calibration, and avoid placing the sensor in an area that may be subject to direct shock, vibration, or dramatic changes in temperature. In addition, the sensor should be kept away from any potential sources of electromagnetic interference. In terms of mechanical connections, it is necessary to strictly follow the instructions provided by the manufacturer, use the correct threaded or flanged joints, and ensure that all joints are tight and leak-free. If necessary, appropriate sealing materials such as Teflon tape or O-rings can be used, while considering the use of support structures to reduce the impact of pipe movement on the sensor.

Electrical connections are also important, and it is necessary to correctly connect the power and signal lines according to the wiring diagram, and take appropriate cable protection measures, such as threading pipes or using cable sheathing, to prevent physical damage. For applications in outdoor or humid environments, special attention should also be paid to the waterproof and dustproof treatment of electrical connections. Considering the characteristics of the working environment, it is critical to select a sensor with the appropriate level of protection (IP level). If the sensor will operate in extreme temperature conditions, it must be confirmed that it can adapt to these conditions; When the medium is corrosive, it is necessary to ensure that the sensor material is compatible with the medium.

Safety regulations can not be ignored, in the dangerous area where there may be a risk of explosion, it is necessary to choose products that meet the relevant explosion-proof standards. During installation, always shut down the system and release all pressure, following local safety regulations and industry standards. For fluids containing impurities or particles, filters can be added to the front end of the sensor; For high temperature liquids, a cooling device can be considered to protect the sensor. After installation, initial calibration is performed to ensure accurate readings, and periodic recalibrations are planned, especially in applications where high accuracy is required.

Finally, record the installation date, model, serial number and other information, and keep the product manual and maintenance guide for future reference.

5.2 What is the operating voltage range of the pressure sensor? Does the power supply affect the performance of the sensor?

The operating voltage range of the pressure sensor varies by model and manufacturer, but common DC supply voltages include 5V, 12V, and 24V. Some sensors may support a wider voltage input range, such as 9-30V DC, which increases their adaptability to different power supply conditions. The exact operating voltage should refer to the recommended value in the specification or data sheet of the specific product.

The power supply mode has a significant influence on the performance of the pressure sensor. First of all, a stable power supply is an important factor to ensure the accuracy of the sensor output signal. Power fluctuations can cause unstable or inaccurate readings, so it is necessary to use a voltage regulator or power regulator to provide a stable power supply. In addition, the quality of the power supply also affects the response time of the sensor; If there is a large ripple (i.e. noise) in the power supply, it may slow down the response speed of the sensor.

In addition to stability and response time, the power supply mode is also related to the reliability and power consumption of the sensor. An inappropriate power supply can cause the sensor to overheat or even damage, so it is crucial to choose a power supply type that meets the manufacturer's recommendations and operates within the specified voltage range. For applications that require low power consumption, such as battery-powered situations, choosing a pressure sensor designed for low power consumption can extend the life of the battery.

6. Maintenance and maintenance of pressure sensor

6.1 What are the methods for routine maintenance of pressure sensors?

Daily maintenance of pressure sensors can effectively reduce the risk of failure of pressure sensors and improve the reliability and safety of the system.

Here are some common maintenance methods:

① Regular inspection and cleaning

Check the exterior of the sensor regularly for physical damage, corrosion, or leaks. Use a clean cloth or soft brush to remove dust and dirt from the sensor and its connectors. Avoid using solvents that may damage the sensor surface.

② Calibration

The sensor is calibrated according to the manufacturer's recommended time interval to ensure the accuracy of the measurement results. This usually involves comparing the sensor to a known standard and adjusting the output. Record relevant data after each calibration, including calibration date, reading changes before and after calibration, etc., in order to track performance trends.

③ Check electrical connections

Check that all electrical connections are secure and re-tighten screws or replace aging cables if necessary. Regularly test the insulation between the lines to prevent short circuit or leakage.

④ Environmental adaptability check

Check that the temperature and humidity in the sensor environment meet specifications. If installed outdoors or in harsh environments, check that shields or other protective devices are intact.

⑤ Media compatibility

Periodically assess the state of the measured medium, such as whether the liquid contains particles or other impurities, and install filters if necessary. Ensure that there is no chemical reaction between the sensor contact parts and the measured medium leading to corrosion and other problems.

⑥ Performance Monitoring

Pay close attention to the working status and output signal of the sensor through continuous monitoring system or regular manual reading. Once any abnormal situation is found (such as large fluctuations in reading and slow response), the use should be stopped immediately and troubleshooting should be carried out.

⑦ Archiving and training

Maintain complete maintenance records, including repair history, calibration reports, etc. Ensure that the personnel responsible for maintenance are properly trained in operation and maintenance and know how to properly handle the equipment.

6.2 How to Perform Calibration? How long is the calibration cycle?

The calibration of a pressure sensor is a critical step in ensuring the accuracy of its measurement results and usually involves comparing the sensor to a known standard and adjusting the output to match that standard. Before starting calibration, you first need to prepare a set of certified standard pressure sources, such as precision pressure gauges or pressure calibrators, and ensure that all connectors, adapters, etc., are clean and free of damage. Next, properly mount the sensor to the calibration device in accordance with the manufacturer's guidelines, ensuring that all connections are tight and well sealed.

Next, set a series of pressure points as reference values, which should cover the sensor's operating range, including zero, full scale, and several other intermediate points. Gradually increase or decrease the pressure, record the actual reading of the sensor at each preset pressure point, and compare the actual reading with the expected standard value. If the deviation is found to be outside the allowable error range, the output of the sensor is adjusted as necessary. Some sensors support software adjustment, while others may require physical adjustment. Adjust and test again until accuracy requirements are met.

After the calibration is completed, a detailed calibration report is prepared, recording the calibration date, standard equipment used, test points and their results, etc., and the report is archived for future reference. For calibration cycles, the recommendations provided by the manufacturer should be followed first, as different types of sensors may have different recommended calibration cycles. In addition, if the sensor operates under extreme environmental conditions or is subject to frequent shock vibrations, more frequent calibration may be required. Certain industries (such as medical, food processing, etc.) also have specific regulations that specify the frequency of calibration.

In general, you can consider calibration at least once a year. For critical applications or high-precision requirements, semi-annual or even quarterly calibration may be required. When performing calibration, it should be performed by trained professionals or entrusted to a professional calibration service provider. At the same time, keep the calibration equipment in good condition, and regularly calibrate them themselves to ensure their accuracy. It is essential to follow the relevant safety procedures throughout the process, especially when dealing with high-pressure gases or liquids. With regular calibration, you can ensure that the pressure sensor always delivers reliable measurement results, thereby improving the performance and safety of the entire system.

7. What are the common faults of pressure sensors?

Pressure sensors may encounter a variety of failures during use, which may be caused by environmental factors, improper installation, aging, or manufacturing defects.

Here are some common pressure sensor failures and their possible causes summarized by INFINITECH:

Inaccurate reading

• Causes: improper calibration, sensor damage, electrical interference, thermal drift caused by medium temperature changes.

• Solution: Recalibrate the sensor, check for physical damage, and ensure that the sensor is away from interference sources such as strong electromagnetic fields.

The output signal is unstable

• Cause: power supply voltage fluctuation, loose wiring, poor contact, internal electronic component failure.

• Solution: Use a regulated power supply, tighten all electrical connections, replace damaged wires or joints, and replace sensors if necessary.

No output signal

• Causes: Power problems (such as open circuit, short circuit), sensor damage, line breakage, or connection errors.

• Solution: Check and repair the power line, confirm that the sensor is working properly, check and correctly connect all lines.

Zero drift

• Reasons: natural wear after long-term use, changes in ambient temperature, mechanical stress.

• Solution: Regular zero correction, if the drift is serious, you need to consider replacing the sensor.

Slow or no response

• Causes: Sensor blockage (for liquid media), diaphragm rupture or deformation, internal circuit failure.

• Solution: Clean or replace the filter to remove the blockage, check the condition of the diaphragm, and replace the sensor if there is damage.

Out of range damage

• Cause: The pressure applied exceeds the maximum measurement range of the sensor.

• Solution: Select the appropriate range of sensors, and add overvoltage protection devices in the system.

Temperature effect

• Reason: the operating temperature is beyond the rated range of the sensor, or the error caused by the temperature is not compensated.

• Solution: Ensure that the sensor works within the recommended temperature range, and consider using a sensor with temperature compensation function.

Mechanical damage

• Cause: Shock or vibration caused by improper installation, corrosive media erosion.

• Solution: Install the sensor correctly, avoid unnecessary mechanical stress, and choose a sensor made of a material compatible with the medium.

Electrical fault

• Cause: Cable damage, wiring errors, lightning strikes, or other electrical accidents.

• Solution: Check and repair the cables, reconnect them according to the correct wiring diagram, and install proper lightning protection devices.

8. Conclusion

In short, the correct selection, installation and maintenance of pressure sensors is essential to ensure their long-term stable operation and provide accurate and reliable measurement data. When selecting a sensor, take full account of application requirements, environmental conditions, and cost-effectiveness to avoid performance issues and additional expenses caused by non-conforming specifications. Proper installation not only includes tight mechanical connections without leakage, but also involves the safety and protection of electrical connections, which can effectively prevent physical damage and electrical failures. In addition, regular inspection, cleaning, calibration, and recording maintenance activities are key to maintaining sensor performance. By following these basic principles, you can not only significantly improve the overall efficiency and safety of your system, but also extend the service life of your equipment and reduce unnecessary downtime and maintenance costs.