What Types of Sensors Are Required by the Trillion-Dollar IIoT Market?

According to research reports by McKenzie, by 2025 the total economic value of the IoT’s nine major applications will reach US$11.1 trillion. Meanwhile, the value of the business-to-business industry represented by smart factories will reach NT$3.9 trillion, accounting for 35% of the IoT’s total value. You couldn’t blame anyone for being tempted by this trillion-dollar Industrial Internet of Things (IIoT) market.

As in other fields of IoT application, the intelligent systems developed for the IIoT fulfil the three main functions of sensing, thinking, and action. The various and ubiquitous sensors in IIoT collectively fulfil the function of "sensing". The data continuously generated by the sensors is what drives the highly efficient operation of the entire IIoT. Without this data, the IIoT would be like an engine without fuel. Therefore, it is no exaggeration to say that he trillion-dollar IIoT starts with a single sensor.

IIoT sensor application scenarios

Since industrial applications are extremely diverse, the classification of IIoT sensors is extensive. Based on application scenarios, the sensors can be loosely divided into three categories.

• Equipment status sensing. This type of sensor has two functions. First and foremost, it monitors the operating status of machinery and equipment, such as the rotation speed of motors, so that the IIoT control center can respond promptly and adjust the the equipment when necessary to restore optimum operating status. Concurrently, it collects data on temperature, vibrations, pressure and other features of the machinery and equipment. Keeping track of their operating status, wear and tear and service lives enables the implementation of predictive maintenance to avoid losses caused by equipment failure and damage.
   
• Production space sensing. This refers to the sensing of the “objects” encountered and processed by the machinery, as well as the surrounding spaces. The demand for this type of sensor is growing especially in industrial sites, where increasing numbers of robots are being introduced. The sensing of operated objects allows machines to accurately identify and operate on targets. Also, the monitoring of the operation space helps machinery and equipment learn the positions and movement of other operators within a given space. Hence they are able to coordinate with each other and avoid situations such as collisions that endanger lives and property. This is especially important for collaborative robots that work with people.
   
• Work environment monitoring. Industrial applications usually require strictly controlled environments with regard to temperature, humidity, air pressure and so on. It is imperative that these variables are maintained within fixed ranges to ensure the optimum performance of machinery and operators. Sudden and unchecked changes to the environment can have disastrous consequences. Hence the deployment of various environmental sensors to help maintain a stable operating environment is another vital task of the IIoT.

Varied selection of sensors

Based on the above three application scenarios, it is relatively easy to identify the types of sensor that will play an invaluable role in the IIoT.

• Temperature and humidity sensors are the most commonly used parameters in industrial applications. They are involved in the monitoring of the equipment’s operating status, the production space and the operating environment.
   
• Pressure sensors are used to measure the pressure of gases or liquids in the internal or external environment of the machinery and equipment. Pressure is another variable that requires high-frequency monitoring in industrial applications.
   
• Vibration sensors monitor vibrations for the purpose of preventive maintenance. They can sense impacts or acceleration, and convert it into an exportable signal to deduce key data such as vibration, displacement, and the thermal expansion of rotors and casings.
   
• Motion sensors can measure information such as operating speed, acceleration, rotation angle, and displacement of equipment. Motion sensors include magnetic resistance sensors, which are used in the control of precision inductive servomotors and are crucial to the accuracy and efficiency of machinery and equipment control.
   
• Force sensors, also known as weight sensors, are widely used in industrial robotic arms to measure the force in the grip or grasp of an object, thus helping to ensure the consistency of the manufacturing process. This type of sensor can also detect and control the strength of robotic arms when it comes into contact with other objects or operating personnel in the production space, thus preventing injuries caused by excessive force during the machines’ operations.
   
• Visual sensors capture visual data. With the development of machine vision (MV), the application of optical cameras in the IIoT will become increasingly extensive. Moreover, the increasing deployment of robots will drive demand for the construction of three-dimensional visual information. To meet this growing demand, the time-of-flight (ToF) optical sensor and other technologies capable of obtaining depth data will undoubtedly be developed.
   
• Ultrasonic/Millimeter-wave (mmWave) sensors can detect objects in dim lighting by emitting ultrasonic waves (mechanical waves) and monitoring the echoes reflected from the object. Thanks to the development of mmWave radar technologies, this efficient and cost-effective solution for obstacle avoidance has become increasingly commonplace. Although a mmWave sensor costs more than an ultrasonic sensor solution, it can obtain more information, including the speed, angle and position of the object, and can sense objects through materials such as walls, plastic and glass. As they become more cost-efficient, mmWave sensors will inevitably start to replace ultrasonic sensors.

Unique new characteristics

Although the sensors utilized in the IIoT vary widely in function and shape, they share certain characteristics when incorporated in an IoT system.

One characteristic that the new generation sensors have in common is intelligence. While traditional sensors only sense and measure the status of the physical environment in terms of temperature, humidity, air pressure, vibration, motion and so forth, industrial sensors plan a more integral role in maintaining reliability and performance. Since the sensors utilized in the IIoT also integrate computing and processing or wireless communication with the basic sensor functions, depending on individual application needs, they form a sensor system that can effectively perform the role of edge computing and make swift and accurate responses based on the sensor data.

Moving forward, the maintainability of the sensors must be improved in view of the ongoing increase in the number of sensors that are being used in the IIoT. Compatibility among sensor products, the application of energy-harvesting technologies, and remote OTA management are just some of the increasingly important priorities in the design of IIoT sensor products.

Clearly, the trillion-dollar IIoT is the driving force behind a new surge of development for industrial sensor products. Keeping abreast of this exciting trend in the IIoT sector will help ensure that our new designs are both relevant and innovative.