Development of display meters and recording meters

With the drastic drop in the price of DCS systems and the widespread use of PLC controllers, computers have performed functions such as display, control operations, and data storage in industrial automation systems. Therefore, digital control instruments and recording instruments that were originally applied have been replaced, but overall, they gradually In atrophy. Many people in the industry believe that the development of digital adjustment meters and recording meters has come to an end, but this time the situation of MICONEX 2004 makes the author question the view. Domestic and foreign companies carrying digital regulating instruments and recording meters exhibit more than three to forty companies, no shortage of companies with an annual output of tens of thousands of units.
Digital adjustment meters and recording meters are among the most common instruments used in industrial automation control systems. From the early 1980s to the mid-1990s, with the rapid development of microelectronics and micro-processing technologies, digital adjustment instruments, multi-channel, universal input, and large-capacity measurement with intuitive, high-accuracy measurement, and PID auto-tuning were introduced. The new record instrument of data electronic storage function, the paperless recorder, has been rapidly developed, occupies an important position in the industrial automation system, and promoted the automation level of various industries such as petroleum, chemical industry, metallurgy, and machinery at that time.
China's rapid economic development in recent years has led to a rapid increase in the number of enterprises, and the use of inexpensive digital control instruments and recording instruments in small-scale, low-level automation, relatively poor personnel skills, and short-established SMEs are very economical. ,Effective. The foreign products focus on the development of dedicated control recording stations and control stations for specialized systems and devices.
Domestic product features
(1) In recent years, domestic digital adjustment meters and paperless recording meters have made considerable progress, thanks to the major contributions made by private technology companies. The main manufacturers of digital regulating instruments include: Shangrun Precision Instruments, Hongrun Precision Instruments, Xiamen Yuguang, Shaoxing Zhongyi Electronics Co., Ltd., and their annual production reaches tens of thousands of units. The recording instrument is mainly a paperless recorder. The manufacturers include Hangzhou Pangu, Zheda Zhongzhong, Shaoxing Zhongyi Electronics, etc. The annual sales volume ranges from thousands to tens of thousands.
(2) The number of domestic products in the market is absolutely dominant, but it also shows that there are many conventional varieties and few featured varieties. The function and quality level of a few factories are quite similar, and there is a lack of features between products.
(3) The performance, appearance and reliability of the instrument are less than that of similar foreign products.
(4) The communication function is already the normal function of the digital adjustment meter and the recording meter, but at present only the Modbus, RS-485, and RS-232 forms have poor openness and it is difficult to access the plant bus automation system.
(5) At present, the domestic product competition is fierce, and the competition means often stay in price competition, and each price is lowered, resulting in a low profit rate of the company. In this way, the company's investment in further scientific and technological development and technological innovation is insufficient, resulting in fewer new products and long launch times.
Foreign product features
(1) Digital regulating instruments and recording instruments have been developed into specialized control stations, recording stations, and network stations. A digital regulating instrument has multi-loop configuration control, multi-channel digital input and output logic control functions, and paperless recorders often have dozens of channel measurement and recording functions, and also include multi-channel digital adjustment functions. It turns out that many typical and difficult-to-control special systems, such as boiler control, carburizing furnace control, and vacuum sintering furnace control systems, require multiple PID combinations. In the past, multiple digital adjustments, manual operators, alarms, and recorders were needed. Now, as long as a dedicated digital adjustment meter or recording meter can be realized, the meter has a variety of communication protocol interfaces and it is convenient for the entire factory automation system. Connected to achieve information exchange.
(2) User-friendly human-machine interface design, which can display multiple information and multiple methods at the same time. The configuration operation has both the traditional operation through the instrument panel button mode, and can also be set on the computer or communicator to download parameters to the instrument through the network.
(3) The instrument is further improved in terms of performance and reliability, and the measurement accuracy is ±0.1%. FS is a universal level. The sampling control period is faster and faster. The original is generally 0.5s, 0.25s, and some of them may even reach the sampling time of 25ms. The fast meter with control cycle has hundreds of thousands of hours of MTBF reliability.
(4) The development of the instrument to the network, many instruments have open DeviceNet, Profibus, CC-Link, Ethernet-Link a variety of bus interfaces to facilitate the connection of factory automation systems.
(5) Due to the development of the instrument itself, digital regulating instruments and recording instruments are more effective in certain areas and control devices than DCS, PLC, etc., and are more cost-effective. There is a lot of room for existence and development.