Intelligent instruments are built upon the development of microelectronics technology. The embedding of very large-scale integrated circuits integrates functions such as CPU, memory, A/D conversion, and input/output onto a single chip, even incorporating PID control components. Furthermore, the application of fieldbus technology allows digital communication between intelligent instruments and control systems to replace traditional analog transmission, significantly improving accuracy and reliability, avoiding the attenuation of analog signals during transmission, and resolving long-standing interference problems. In addition, digital communication saves considerable amounts of cabling, installation materials, and installation costs.
The Development History of Intelligent Meters and Their Technologies
Following the development of analog-based electric unit combination instruments and the DDZ-S series instruments featuring hybrid analog-digital technology, Honeywell pioneered a new generation of intelligent pressure transmitters for the manufacturing industry in 1983. This marked the transition from analog to digital intelligent instruments. These intelligent transmitters at the time featured high precision, long-distance calibration, and flexible configuration, informing users that while the initial purchase cost was high, it would be offset by lower operating and maintenance costs. In the following decade, intelligent pressure transmitters from other foreign companies were also adopted on some production lines, including Rosemount, Foxboro, YOKOGAWA, Siemens, E&H, Bailey, Fuji, and ABB. However, due to the lack of high-speed intelligent communication standards, the relatively low demand for high-precision monitoring from users, and weak training and other service mechanisms, the application of intelligent transmitters at that time was not promising, accounting for only about 20% of the market.
With the rapid development of microelectronics, computers, networks, and communication technologies, and the continuous improvement of integrated automation, intelligent instruments, which are widely used in industrial automation, have also experienced rapid technological advancements over the past two decades. Currently, foreign intelligent instruments occupy the vast majority of the international application market. How to combine current industrial application experience with intelligent instruments and quickly track international cutting-edge technologies for application in the development and research of intelligent instruments in my country has become a prominent issue for revitalizing the national intelligent instrumentation industry.
Advantages and features of smart meters
The widespread application of intelligent instruments in industrial automation benefits from their outstanding technological advantages and characteristics, such as high stability, high reliability, high precision, and ease of maintenance. Taking intelligent transmitters as an example, intelligent instruments possess the following advantages:
(1) High-precision intelligent transmitters have high precision. Utilizing the built-in microprocessor, they can measure the effects of static pressure and temperature changes on the sensing element in real time. Through data processing, nonlinearity is corrected, and hysteresis and reproducibility are compensated, making the output signal more accurate. Under normal circumstances, the accuracy is ±0.1% of the maximum range, and the accuracy of digital signals can reach ±0.075%.
(2) Strong functionality
Intelligent transmitters have a variety of complex computing functions. Relying on internal microprocessors and memory, they can perform square root extraction, temperature and pressure compensation, and various complex calculations.
(3) Wide measurement range
The maximum range ratio of ordinary transmitters is 10:1, while that of intelligent transmitters can reach 40:1 or 100:1, with a range shift of up to 1900% and -200%, reducing the number of transmitter specifications, enhancing versatility and interchangeability, and bringing many conveniences to users.
(4) Strong communication function
All intelligent transmitters can be operated via handheld devices. The handheld device can be plugged into the corresponding socket on the transmitter in the field, or it can be connected to the transmitter's signal line from the control room to adjust and change the zero point and range. Some transmitters have both analog and digital output modes (such as the HART protocol), laying the foundation for fieldbus communication.
(5) Comprehensive self-diagnostic function
The fault results of the transmitter's self-diagnosis can be retrieved through the communicator.
Suggestions on the future development direction of smart meter technology and its applications
(1) The level of intelligence of smart meters needs to be further improved.
The level of intelligence of a smart instrument reflects the breadth and depth of its application. Currently, smart instruments are only at a relatively low level of initial intelligence. However, certain special processes and applications place higher demands on the intelligence of instruments. Current intelligent theories, such as neural networks, genetic algorithms, wavelet theory, and chaos theory, already have a potential application foundation. This means that we have the necessity and the ability to make great efforts to develop advanced intelligent instrument technologies in combination with specific application needs.
(2) The stability and reliability of smart meters need long-term and continuous attention. The stability and reliability of instrument operation are the primary concerns of users, and smart meters are no exception. With the continuous expansion of smart meter technology, new smart meters will be launched on the market one after another. This requires us to always adhere to one principle: the application of each new smart technology needs to be tested in practice, and whether users have the confidence and courage to be the "first to try". This requires the parallel development of security and reliability technologies.
(3) The potential applications of smart meters need to be maximized.
Currently, the practical applications of smart instruments in the field of industrial automation have not maximized their functions, with only about half of their overall capabilities being utilized. The main reason for this situation is that the overall architecture of the control system ignores the technological advantages of fieldbus. This requires instrument manufacturers and users to establish a good partnership, strengthen long-term cooperation, and promote long-term benefits through short-term investment. By establishing a control system architecture of "smart instrument + fieldbus", an optimized investment concept can be established to achieve a harmonious and win-win goal.
(4) Continue to increase investment in the development of domestic smart meters.
The development and application of intelligent instruments still require a relatively long period of maturation. The development of intelligent instruments in China is facing even greater challenges. This situation calls for the domestic instrument industry to jointly explore the development of intelligent instruments, cope with the fierce international market competition, shoulder the historical mission of the instrument industry, and continue to increase investment in the development of domestic intelligent instruments under increasingly favorable national and governmental support policies, while adhering to the close integration of production, learning, and research.
