High-tech sensors are becoming a more common sight across industrial workplaces. Some of the most versatile and essential are vibration-monitoring technologies like strain gauge sensors and accelerometers. These monitoring devices serve crucial functions across many use cases, so learning more about them is important to embracing Industry 4.0.
What Does a Vibration Sensor Do?
A vibration sensor detects and quantifies vibrations. In many industrial applications, that means seeing how much a piece of equipment shakes. Businesses also use these technologies to test products, watch for environmental hazards and even track human health.
Predictive maintenance is one of the most helpful applications for vibration monitoring in industrial settings. This practice uses strain gauge sensors and similar technologies to analyze equipment health, alerting workers when a machine needs work. These timely, data-driven repair alerts can offer savings of up to 40% by preventing breakdowns.
Vibration sensors can also ensure research machines like shakers that vibrate test subjects work properly. Alternatively, manufacturers can use them to monitor airflow, test pressure or check quality control on products with moving parts.
Types of Vibration Sensors
Vibration sensors have a wide range of applications and come in many forms. Here are five of the most common types across use cases today.
Accelerometers
Accelerometers are the most popular type of vibration sensor, largely due to their versatility and relative simplicity. These devices work by mounting to the test subject and measuring its acceleration. Piezoelectric materials convert movement into electrical signals, so as the sensor and the object it’s attached to move, it registers that motion as a hard data point.
Even though accelerometers don’t technically measure vibration, businesses can infer levels from acceleration data. The more sudden acceleration one of these sensors experiences, the more dramatically it vibrates.
Piezoelectric sensors are relatively straightforward, so accelerometers are often one of the most affordable types of vibration sensors. However, they require other equipment to collect and analyze their data.
Strain Gauge Sensors
Strain gauge sensors are another popular type of vibration monitoring system. These devices look like thin foil sheets housing an electrical grid. These components create electrical signals that reveal the strain on an object as they stretch and compress.
Small, rapid changes in strain reflect vibrations, but businesses can also use these sensors to measure mechanical stress directly. As a result, these are an ideal choice for predictive maintenance applications. Studies have found that strain gauges are more sensitive to damage detection than acceleration-based sensors, so they can detect potential issues sooner.
Strain gauges are also inexpensive and highly versatile, as their small, flexible form factor lets them attach to virtually any surface. Of course, they have downsides, too. They require careful installation and specialized equipment to use in practicality.
Capacitive Displacement Sensors
Capacitive displacement sensors don’t contact any vibrating surfaces, unlike accelerometers and strain gauges, which attach directly to their test subjects. Instead, they measure the distance between themselves and the object in question with magnetic fields. Fluctuations in that distance reveal how much a surface is vibrating.
Despite having no contact with what they measure, capacitive displacement sensors are highly accurate. Their lack of motion reduces noise that may interfere with the signal and can help them last longer.
The biggest downside to a non-contact vibration sensor is that it can only measure relative vibration between the subject and device. Machines that vibrate in a different direction than the sensor is facing may not be detected. These sensors also need clean environments and consume a lot of power.
Microphones
Microphones are also a type of vibration sensor, though many people may not initially think of them that way. Sound waves are vibrations in the air, so a sensitive microphone or similar pressure-sensing device can serve as a vibration monitoring system.
Like capacitive displacement sensors, microphones are non-contact sensors, which can be either an advantage or a downside, depending on the situation. They can also provide a wider range of data than other sensor types, and many can detect frequencies that other devices may struggle to register.
Microphones are best suited for high-precision, relatively low-vibration applications, given their sensitivity. Therefore, they have limited industrial use cases. Some shakers, which need vibration sensors, can generate noise above 90 decibels, making microphones unideal.
Handheld Vibration Meters
Handheld vibration meters often use accelerometers, but they’re unique enough to deserve their own category. These are portable devices workers hold up against equipment for immediate vibration analysis.
Handheld meters are meant for quick, often in-the-field ratings, so they don’t log data for long stretches. As a result, they’re not ideal for long-term analysis or predictive maintenance but are excellent for preventive maintenance checks and workers at remote job sites. They can also be expensive, but they don’t require any peripheral equipment, making their costs more manageable.
How to Choose the Right Vibration Sensor
Because every type of vibration sensor works differently, each is better suited for different use cases. As a result, companies must review their needs and available options to determine the right product for their unique circumstances.
First, organizations should consider why they’re monitoring vibrations. Unplanned downtime costs manufacturers $50 billion annually, so predictive maintenance is one of the most common use cases. Strain gauge sensors are one of the best solutions for these applications, but companies with less time or tech talent to install them may consider easier-to-use accelerometers.
Cost is another big factor. Accelerometers and strain gauges offer low-cost monitoring, but the extra equipment they need may increase expenses if companies don’t have compatible devices. Alternatively, handheld vibration meters are more expensive upfront but have lower ongoing costs in workflows that don’t require continuous monitoring.
Other factors to consider include the shape of the equipment to monitor, the environment around it and the company’s experience with similar devices. Talking to providers offering multiple sensor types can help businesses find the best solution for them.
Make the Most of Available Sensor Technology
Vibration-sensing technology covers various devices and use cases, from accelerometers to microphones to strain gauge sensors. Learning about these different technologies and their ideal applications can help businesses make the most informed decisions. They can then use these sensors to their fullest potential.
Emily Newton is the Editor-in-Chief of Revolutionized Magazine, an online publication that explores innovations in science and technology.
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