LED display control system (LED Display Control System) is a system that controls the correct display of LED large screens according to user needs. The online version is also known as the LED information release control system, which can control each LED terminal through the cloud system. The stand-alone version is also known as an LED display controller or LED display control card. It is the core component of the LED display. Mainly responsible for converting external video input signals or onboard multimedia files into digital signals that are easily recognizable on large LED screens. , so as to light up the LED large-screen device, similar to the graphics card in the home PC, the difference is that the display in the PC is CRT/LCD, etc., and the display in the system is the LED large screen. The access signal mode can be divided into the synchronous system and the asynchronous system.
- According to the display mode, the LED display system is divided into three categories
1.1 Graphical display system
Generally, the LED display that displays graphics and text is called a graphic screen. The main feature of the graphic screen is that each light-emitting device in the LED dot matrix is only on or off, and cannot control the strength and weakness, that is to say, this screen has no grayscale control.
1.2 Image display system
Image displays are relative to graphic displays, referring to those with grayscale displays that display a more vivid picture. The main feature of the image screen is the use of limited grayscale and color modulation to display images that do not require high color and grayscale.
1.3 Video display system
Based on the study of the skimming screen control system, the LED display that can receive the video signal and display a moving, clear, full-color image is called a video display.
- Depending on the control mode, we will divide the display system into two categories
2.1 Communication display system
The communication display is asynchronous. Asynchronous mode refers to the LED screen itself having the ability to store and auto-play, and display the edited text and non-grayscale picture information or Chinese characters on the PC position code and picture. Numbers, etc., and various control instructions are transmitted to the LED screen controller through the serial port or other network interfaces, and various data information per-stored in the controller is called, and the received instructions are processed into the dot matrix data required for the display as needed, and released to the display. This type of screen generally does not have multi-level grayscale display capabilities, is mainly used to display text and simple graphic information, and can be networked on multiple screens. This approach must require a controller with a CPU to process the information.
2.2 Real-time mapping screen system
The real-time map screen is a synchronous display, the basic function is to realize the real-time mapping of the computer screen content of the LED display, including displaying video images with the support of multimedia cards. Take out the data from the featured port of the host graphics card or video main control card, take out the data to be displayed after the graphics card is processed and then send it to the LED display after certain processing of the data. This method can be implemented without a controller with a CPU, or even by making a hardware card.
The 256-level grayscale LED display system can make the LED display and the computer synchronous display achieve a high-performance display effect. The 256-level grayscale LED display control consists of a multimedia card, a video controller, a long-line driver, a receiving card, and a display unit. The video controller takes the digital display signal from the standard display interface of the multimedia card and converts it into the signal format required by the display. The control signal can also be obtained from the computer standard interface, and the user can complete the control of the LED display through the computer software. Adjusted so that the display can adapt to different specifications of multimedia cards, with a high degree of compatibility.
- Classification of communication methods
3.1 Wired communications
A communication method that uses tangible physical media such as cables and optical fibers as the medium. As far as applications are concerned, data transmission is generally carried out through dedicated channels, which is costly. It is believed that in the future, wired communications based on the public network will be more widely used. The use of the Internet to transmit data is also one of the main methods used by the system
3.2 Wireless communication
The method by which the LED screen controller sends information from the monitoring center through radio waves within a communication distance with the monitoring center. This approach saves system investment, shortens the construction cycle, and reduces the likelihood of system theft. This mode of communication is similar to the form of mobile phone text messages, using GSM, GPRS, or CDMA networks for transmission, or using broadcast towers, using FM or AM to send and receive signals.
LED display asynchronous control system is also known as LED display offline control system or offline card. It is mainly used to display a variety of text, symbols, and graphics or animations. The screen display information is edited by the computer, pre-installed into the frame memory of the LED display through the RS232/485 serial port, and then the playback is displayed in a loop screen by screen, and the display method is colorful and changeable. Its main characteristics are simple operation, low price, and wide range of use. The LED display simple asynchronous control system can only display digital clocks, text, and special characters. Led display graphic asynchronous control system in addition to the function of a simple control system, the biggest feature is that you can control the content of the display by area. Supports analog clock display, countdown, picture, table, and animation display. It has the functions of a time switch, temperature control, humidity control, and so on.
LED display synchronous control system is mainly used for real-time display of video, graphics, notifications, etc. Mainly used for indoor or outdoor full-color large screen display. LED display synchronous control system to control the LED display works in the same way as a computer monitor. It maps images to computer monitors in real-time at an update rate of at least 60 frames per second, often in multi-grayscale displays. Ability to achieve multimedia advertising effects. Its main characteristics are strong real-time, rich expression, complex operation, and expensive. A set of LED display synchronous control systems is generally composed of a sending card, a receiving card, and a DVI graphics card.
The array control system, LED full-color display control system
The “array” control system consists of the main control board, several sub-control boards, and several scanning boards installed in the display cabinet, which is equivalent to using a set of control systems in each cabinet for control. This structure fully improves the reliability and display effect of the display, the effect is more obvious and solves the problems of low frame changing frequency, insufficient grayscale, and poor color uniformity when the high-end LED display plays video. Issue. According to the appraisal of the expert committee organized by the Science and Technology Bureau, the technology has reached the level of domestic leading and international similar products.
The birth of this generation of control systems has enhanced the technical advantages of Yuanheng Optoelectronics in screen control and further improved the processing technology of display signals.
After the use of the “array” control system, the frame-changing frequency of the display can first be increased from about 60Hz to more than 120Hz, which is far greater than the resolution ability of the human eye, so that people can watch without any strobes and water ripples. appears to improve display quality.
Secondly, the grayscale of the red, green, and blue primary colors on the display can be increased from 256 to 1024, making the color more vivid, the color reproduction better, and the displayed image more realistic.
Finally, the LDVS signal is used for transmission, which minimizes the loss of the signal, synchronizes the display content of the entire display, and improves the consistency of the display.