National standard GB7665-87 under the sensor is defined as: "can feel the provisions is measured and according to certain rules (laws of mathematical functions) is converted into usable signal devices or device, usually by sensitive components and conversion components".
China's iot alliance between colleges think, existence and development of sensors, let objects have sensory, such as touch, taste and smell let objects become live up slowly. "
"Sensor" in the new wei type in the dictionary is defined as: "receive power from a system, usually in a different form will be sent to the second power device in the system".
In order to obtain information from the outside world, people must use sensory organs. And people's own sense organs, alone in the study of natural phenomena and laws as well as the production activities and their functions are not enough. In order to adapt to this situation, it needs to sensor. So it can be said that the sensor is the extension of human facial features, also called features.
The arrival of the new technology revolution, the world begin to enter the information age. In the process of the use of information, the first thing to solve is to obtain accurate and reliable information, the sensor is access to natural and production information in the field of the main ways and means.
In the process of modern industrial production, especially in automatic production, want to use a variety of sensors to monitor and control the various parameters in the process of production, make the equipment working in normal state or the best state, and achieve the best quality products. Therefore, there is no many excellent sensors, modern production will lose the foundation.
In the study of basic subjects, is more prominent position sensor. The development of modern science and technology, in the many new fields: for example, on the macro to observe thousands of light-years across the vast universe, to observe small to FM on micro particle world, longitudinally to observe the celestial evolution for hundreds of thousands of years, short to s instant response. In addition, the understanding of deepening material, develop new energy, new materials such as plays an important role in all sorts of extreme technology research, such as ultra high temperature, temperature, ultra-high pressure and ultra-high vacuum, strong magnetic field, the ultra weak magnetic field, and so on. Obviously, for a large number of human senses can not directly access information, not appropriate to the sensor is not possible. Many barriers to basic science, first is the object information acquisition is difficult, and some new mechanism and the presence of the highly sensitive detection sensor, often lead to breakthroughs in this field. The development of some sensors, tend to be the pioneer of the development of some edge discipline.
Sensor has already penetrated into such as industrial production, the development, Marine exploration, environmental protection, resource investigation, medical diagnosis, biological engineering, and even the protection of cultural relics and extremely extensive areas. It is no exaggeration to say, from the vast space, to the mighty ocean, and all kinds of complicated engineering system, nearly every modern project, is inseparable from the various sensors.
Therefore, sensor technology is important in the economic development, promoting social progress, it is very obvious. All countries in the world attach great importance to the development of this field. Believe in the near future, sensor technology will be a leap, reached new levels commensurate with its important status.
Sensor's features include: miniaturization, digital, intelligent, multi-functional, systematic and network, it not only promote the transformation and upgrading of traditional industries, but also possible to establish a new industry, becoming the new economic growth point in the 21st century. Miniaturization is built on a microelectronic mechanical system (MEMS) technology, on the basis of has been successfully applied in silicon devices made of silicon pressure sensor.
Often used the sensor function compared with human five sense organs to:
Photosensitive sensor, vision
Acoustic sensors, hearing
Gas sensor, the sense of smell
Chemical sensors, sense of taste
Pressure sensitive, win min, fluid sensor, touch
The classification of the sensitive element:
Physics class, based on force, heat, light, electricity, magnetic and physical effect, etc.
Chemical class, based on the principle of chemical reaction.
Biology class, based on the molecular recognition function such as enzymes, antibodies, and hormones.
Usually according to the basic awareness can be divided into thermal sensor, light sensor, gas sensor, force sensor, magnetic sensor, moisture sensor, acoustic sensor, radiation sensitive element, color sensor and sensor etc. 10 categories (others have sensitive element 46 class).
Resistive sensors
Resistive sensors will be measured, such as displacement, deformation, force, acceleration, humidity, temperature, etc, these quantities into resistance transformation type such a device. Mainly include the resistance strain type, pressure type, heat resistance, thermal resistance, gas sensitive, humidity sensitive a resistive sensor.
Frequency conversion power sensor
Frequency conversion power sensor based on the input voltage, current signal to communicate sampling, then samples values through cable, optical fiber transmission system are connected to the digital quantity input secondary instrument, digital quantity input secondary instrument to the operations of the sampling values of the voltage, current, voltage RMS, current RMS can be gained, the fundamental voltage, the fundamental wave current, harmonic voltage and harmonic current, active power, power of fundamental wave and harmonic power of parameters.
