Since the advent of column load cell using adhesive resistance strain gauges in the early 1940s, after more than 60 years of improvements and developments, the structural design, manufacturing process, comprehensive performance indicators, stability, and reliability have reached relatively high levels. High level, it has been widely used in various electronic weighing instruments and weighing measurement and control systems. With the advancement of science and technology and the improvement of the automation level of industrial processes, especially the development of digital technology and information technology, the application of digital technology and digital systems in weighing measurement and control systems have become more and more demanding. In order to achieve the digital and intelligent electronic weighing instrument, the digital weighing system is used to break through the limitations of the analog weighing system and other requirements. As we all know, digital weighing systems require weighing load cells and weighing instrument systems to output in digital form. The analog load cell currently in use, due to the resistance strain conversion principle, determines that no matter what kind of resistance strain gauge is used for manufacturing, it cannot produce an output signal with digital characteristics by itself, and the output analog signal is small, generally, 20} 40mv; short transmission distance; poor anti-interference ability; complex weighing display control instruments; inconvenient installation and debugging and other congenital defects. It can't adapt to the digital and intelligent requirements of electronic weighing instruments. Therefore, people pay more attention to the interface between the analog weighing load cells and digital weighing systems and digital intelligent weighing load cells. Some famous foreign weighing load cell manufacturers have carried out a lot of research work on this and achieved breakthrough technology. As a result, a variety of products with independent intellectual property rights have been developed.
As early as 1983, in order to meet the needs of industrial process automation, the American TOLEDO (now METTLER TOLEDO) company introduced the "digital" (DIGITAL) concept and gradually applied it to the weighing field. Committed to researching the use of microprocessor technology and digital compensation technology to combine it with the traditional strain-type load cell technology. After years of hard work, the rocker-type digital intelligent load cell has been developed. The US STS company also introduced an integrated digital intelligent weighing load cell at the 1988 National Weighing Apparatus Exhibition. Both are based on the basic principles of analog load cells, using modern electronic technology and computer software technology to develop new types of load cells. That is, more than 10 components such as amplification, filtering, A/D conversion, microprocessor chip, and temperature-sensitive components are added to the analog load cell. The use of scale conversion, digital filtering, digital zeroing, digital compensation, and other technologies and Process manufacturing is completed. The manufacturing process, testing items, test methods, and supporting weighing instruments of digital intelligent load cells are quite different from those of analog load cells. Therefore, the digital intelligent weighing load cell is a system project jointly researched and developed with weighing instruments.
The digital intelligent load cell has a large output signal. A digital signal is a group of high and low-level signals with a format and regular composition, generally ±SV; strong anti-interference ability such as radiofrequency electromagnetic field radiation; long signal transmission distance, general It can be up to 150m, and it can exceed 600m with additional power supply; it is easy to install and debug; it is easy to realize intelligent control and other characteristics, which completely overcomes the shortcomings of analog weighing load cells. It is a digital electronic weighing instrument, automatic weighing measurement, and control system, which requires automatic The first choice for calibrated weighing systems, various batching scales with complex structures, volume scales, and super-large electronic weighing instruments.
From the perspective of the variety, structure, and use of electronic weighing instruments, digital smart load cells cannot completely replace analog load cells. In a relatively long period of time in the future, analog load cells will still be the development of load cells. And the mainstream of the application. But we must pay attention to and study the digital intelligent weighing load cell and its application in the digital weighing system.
