Automation instruments at the turn of the century

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The 21st century has come, and people will enter the information age characterized by knowledge economy. Microelectronic technology, computer technology, communication network technology and automation technology will continue to develop at a high speed. As a tool of industrial automation technology, automatic instruments and devices will also enter a real era of digitalization, intelligence and networking

sensing technology, computer technology and communication technology together constitute the three foundations of modern information. Some experts believe that in the field of computer and automation, the hot spot in the 1980s was personal computers, and in the 1990s was computer networks, while the hot spot in the first decade of the 21st century is likely to be sensing, execution and detection. This prediction is well founded. In recent years, the development of microelectronics, micromachines, new materials and new processes and the wide application of computer and communication technology will likely create a new generation of sensing and detection systems. Some people call it intelligent sensing technology or modern sensing technology. Its combination with fieldbus technology will have a significant impact on the technical development of automatic instruments and devices

many articles have discussed the development of industrial automation and industrial control computers in the 21st century. This paper only introduces the recent articles and the author's understanding, and introduces the technical progress of measuring instruments and actuators, in order to carry out more discussion and innovation

detection instruments and actuators are the basis of automation of production process and modernization of operation and management, which are particularly valued by people. With the development of industrial automation technology, they play an increasingly important role, because there is no instrument with good performance, high precision and reliable quality to detect all kinds of relevant information, and it is empty talk to achieve a high level of automation

in terms of industrial process detection, the conventional detection of temperature, pressure, flow and material level has a relatively mature technical foundation and can be as large as 10 ℃ or above in serious cases. The main characteristics of the new generation of detection instruments are digitalization and intellectualization. They take microcomputer as the core, which can automatically zero, linearize, compensate for the changes of environmental factors, and configure graphic display instruments to visually express the measurement results. In terms of detection technology, new technologies such as automatic analysis and processing of experimental results by ultrasonic software, microwave and laser are being widely used to solve special measurement problems encountered in different industrial fields and improve performance requirements. Therefore, the urgent task of detecting instruments and actuators is to actively improve the existing measurement methods, further improve innovation and realize computerization and intellectualization; On the other hand, we should adopt new measurement principles, develop new detection instruments, and expand the new field of automatic detection. The following will introduce the technological progress of several measuring instruments and actuators that people pay attention to, such as flow, pressure and material level, when many enterprise users purchase tensile testing machines

1 distributed optical fiber temperature sensing network

professor wuqiufeng of Tsinghua University mentioned in the article "Some Thoughts on industrial control in the 21st century": the combination of intelligent sensing technology and computer network technology produces the concept of intelligent sensing network. It will be committed to the research of intelligent sensor network communication functions and the integration of various technologies, so as to achieve the integration and collaboration of information collection, transmission and processing, which will have an impact on industrial control and integrated automation

in connection with this technical trend, first of all, a distributed optical fiber temperature sensing network for industrial process detection is introduced. It is a real-time, multi-point optical fiber temperature measurement system. It is a high-tech developed in recent years for real-time measurement of space temperature field. It has become a new detection method and technology in industrial process control. The optical fiber in the system is both a transmission medium and a sensing medium. Using the temperature effect of optical fiber back Raman scattering, the temperature field at each point in the space where the optical fiber is located modulates the intensity of back Raman scattering in the optical fiber. The back Raman scattering photoelectric signal with temperature information is collected by wavelength division multiplexer and photoelectric detector, and then the temperature information is extracted from the noise in real time and displayed after signal processing and demodulation, It is a typical laser fiber temperature communication network. 1. A 2km optical fiber with multiple sections of pressure maintaining test can be set, which can collect 1000 temperature information and carry out spatial positioning. It has been applied to the automatic fire temperature alarm system of coal mines and tunnels, as well as the temperature alarm of oil depots and dangerous goods warehouses and the temperature distribution measurement of large equipment. The sensing optical fiber of the distributed optical fiber temperature sensing network is uncharged, resistant to radio frequency and electromagnetic interference, flame-proof, explosion-proof, corrosion-resistant, high voltage and strong magnetic field, ionizing radiation, and can operate safely in a harmful environment. The system has self calibration, self calibration and self-detection functions

in order to track the application of high-tech in real-time detection of industrial processes, we expect that this kind of intelligent sensor network will be more developed

At the turn of the century, there is no new instrument in the flow detection technology. However, various flow instruments with truly intelligent functions will flourish. For example, the development of intelligent differential pressure transmitter has made people see that the throttling device will still have strong vitality

integrated throttling flowmeter is a flow measurement system that integrates throttling device, differential pressure transmitter and flow display device. It introduces the concept of throttling fixed value, which makes the differential pressure flowmeter step up to a new level and is an innovation of flow instruments. Experts said that a new glorious period of differential pressure flowmeter is coming

the nozzle of the integrated throttling flowmeter is preferably throttling parts (orifice plate can also be selected), which does not need real flow calibration, corrosion resistance, small pressure loss, long verification cycle, convenient for users to replace, convenient for mass production, and reduce the cost of throttling parts; It integrates the throttling device with the differential pressure transmitter, which can eliminate the possible additional errors caused by eccentric or non vertical installation on site. It not only ensures the installation accuracy and measurement accuracy, but also shortens the pressure pipeline, reduces the failure rate, and improves the dynamic characteristics, which is of great significance to the automatic control system. It is equipped with a wide range differential pressure transmitter and display device, which can easily migrate and expand the range of the throttling device, so that the range of the flowmeter can reach 6:1 ~ 10:1. It adopts real-time calculation for the flow coefficient and expandable coefficient, and looks up the density table, so the uncertainty can be ignored to ensure that the measurement accuracy can be greatly improved. According to the recent information, the integrated throttling flowmeter has been widely used in new factories and has a broad market prospect

3 electromagnetic flowmeter

among many flow instruments, electromagnetic flow

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