Linhao Power Technology takes you step by step to understand the application of digital time relay in industrial control
Digital time relays belong to the category of low-voltage electrical appliances. If classified according to the classification, they should be classified as electromechanical control electrical appliances of low-voltage electrical appliances. They are a kind of machine tool electrical appliances commonly used in automatic control systems. Its development history can be traced back to the 1970s. The original traditional electric digital time relay or the delayed trigger time control circuit completed with RC charging circuit and single junction transistor has been widely used to date. Multi-delay function (power-on delay, on-delay, power-off delay, off-delay, reciprocating delay, interval timing, etc.), multi-setting method (potentiometer setting) Setting, digital dial switch, button, etc.), multiple time base selection (0.01s, 1s, 1m, 1h, etc.), multiple working modes, digital time relay with LED display. Because it has many advantages such as high delay accuracy, wide delay range, and intuitive delay display during the delay process, it is incomparable with traditional digital time relays, so it has basically replaced the traditional digital in the field of automatic control today. Time relay.
Lin Hao Electric takes you step by step to understand the application of digital time relay in industrial control
Although the time controller started late in China, it has also made great progress in the field of digital time relays. In recent years, with the continuous development of China's electronic technology and the large number of domestic special-purpose digital time relay chips, a large number of research and development and application have been made. To a certain extent, domestic digital time relays have made great progress in terms of appearance and product performance. Especially on the basis of the special chip, the chip masking technology is adopted, the core part of the relay is masked on the printed circuit board, so that the digital time relay is changed from LED digital display to LCD liquid crystal display, plus the universal use of SMD SMD electronic components make the appearance of the product more compact and product performance more stable. Users can preset the time or control mode through the dial or function buttons on the panel peripherals during use. Some products from the specific use Basically, it can be interchanged with foreign products.
In summary, the digital time relay is a controller whose delay function is realized by electronic circuits. It can be widely used for time control and indication in automatic control circuits.
Digital time relays are widely used as automatic control devices, especially when they are used in the environment where there are many electrical devices in the low-voltage electrical control network. The problem of electromagnetic interference becomes more serious. The damage of the internal components that make up the digital time relay is not the main cause of the failure (failure) of the digital time relay at this time, but the various interferences in the application place directly enter the digital time relay through electromagnetic coupling and capacitive coupling. Interfering with its normal delay control. Whether the digital time relay can work normally under this interference environment often affects the normal logic function of the entire automatic control system, and may even cause large quality accidents and economic losses. Therefore, digital time relays should have high reliability and anti-interference ability in various harsh environments. That is to say, digital time relays must have good electromagnetic compatibility performance. Only in this way can they improve their product quality and improve their own market. Competitiveness.
The development of digital time relays has been completed by early separation devices. Now there are dedicated CMOS digital time relay chips to replace them. Regardless of time accuracy, the delay method has been greatly developed, especially recently. For several years, programmable logic controllers (PLCs) have been widely used in the field of automatic time control because of their versatility, good flexibility, complete hardware, complete programming methods, and easy to learn and high reliability. The time relay market has occupied the corresponding market share, and this trend is still gradually expanding. It may be that in the near future, PLC will play a more important role in the field of automatic control.