The principle of displacement sensors

Displacement sensors, also known as linear sensors, are divided into inductive displacement sensors, capacitive displacement sensors, photoelectric displacement sensors, ultrasonic displacement sensors, and Hall displacement sensors. Inductive displacement sensor is a linear device that belongs to metal induction. After the power is turned on, an alternating magnetic field is generated on the sensing surface of the switch. When a metal object approaches this sensing surface, eddy currents are generated in the metal to absorb the energy of the oscillator, causing the output amplitude of the oscillator to decay linearly. Then, based on the change in attenuation, the purpose of non-contact object detection is achieved.

Introduction to displacement sensors　 　 　

Inductive displacement sensors have no sliding contacts, are not affected by non-metallic factors such as dust during operation, and have low power consumption, long lifespan, and can be used in various harsh conditions. Displacement sensors are mainly used for intelligent control of analog quantities in automated equipment production lines. Displacement is a quantity related to the movement of an object's position during motion, and the range of measurement methods for displacement is quite extensive. Small displacement is often detected by strain gauges, inductors, differential transformers, eddy current sensors, and Hall sensors, while large displacement is often measured by sensing technologies such as inductosyn, grating, capacitive grating, and magnetic grating. Among them, grating sensors are increasingly widely used in industries such as machine tool processing and detection instruments due to their advantages of easy digitization, high accuracy (currently the highest resolution can reach the nanometer level), strong anti-interference ability, no human reading error, convenient installation, and reliable use.

Principle of displacement sensor

　 　
The metrological grating utilizes the Moir é fringe phenomenon of the grating to measure displacement& Amp; Ldquo; Moore& Rdquo; Originally from the French word Moire, it means water ripple. A few hundred years ago, French silk workers discovered that when two thin layers of silk were stacked together, a ripple like pattern would be produced; If the thin silk moves relative to each other, the pattern also moves accordingly, and this strange pattern is called Moire stripes. Generally speaking, as long as curve clusters with a certain period overlap, Moir é fringes will be generated. There are two types of metrological gratings in practical applications: transmission grating and reflection grating; According to their working principles, they can be further divided into radiation gratings and phase gratings; According to their purpose, they can be divided into linear gratings and circular gratings. Let's take the transmission grating as an example for discussion. The transmission grating ruler is uniformly engraved with parallel lines, namely grating lines. A is the width of the line, b is the width of the gap between the two lines, and W=a+b is called the grating spacing. At present, the commonly used gratings in China are carved into 10, 25, 50, 100, 250 lines per millimeter. Two gratings are required for measuring displacement using the transverse Moire fringes of the grating. A grating is called the main grating, and its size is consistent with the measurement range; The other piece is a very small one, called an indicator grating. In order to measure displacement, it is necessary to add a light source on the main grating side and a photoelectric receiving element on the indicating grating side. When the main grating and the indicator grating move relative to each other, the moir é fringes move due to the shading effect of the grating. The photoelectric element fixed on the side of the indicator grating converts the change in light intensity into an electrical signal. Due to the limited size of the light source and the diffraction effect of the grating, the signal is a pulsating signal.

Prospects for sensor market development

The sensor market report from consulting company INTECHNOCONSULTING shows that the global sensor market capacity in 2008 was $50.6 billion, and it is expected that the global sensor market will reach over $60 billion in 2010. According to the survey, Eastern Europe, the Asia Pacific region, and Canada have become the fastest-growing regions in the sensor market, while the United States, Germany, and Japan remain the regions with the largest distribution of sensor markets. On a global scale, the fastest-growing sensor market is still the automotive market, followed by the process control market, which is optimistic about the future of the communication market. At present, the global sensor market is showing a rapid growth trend amidst constantly changing innovation. Experts point out that the main technologies in the field of sensors will be extended and improved on the existing basis, and countries will compete to accelerate the development and industrialization of new generation sensors, and competition will become increasingly fierce. The development of new technologies will redefine the future sensor market, such as the emergence and expansion of market share of new sensors such as wireless sensors, fiber optic sensors, intelligent sensors, and metal oxide sensors.