Common interfaces
- Yellow interface T08: typically connects to indoor F3.75 or F5.0 module boards.
- Black interface T12: typically connects to P10 single- or dual-color module boards.
- Blue interface T75: typically connects to full-color 75-pin module boards. Current mainstream full-color module interfaces are 75 and 320 (for fine pitch). Using the Yangbang BX-6S1 as an example, the functions of each interface are shown below.
What is an LED display control system
An LED display control system, also called an LED controller or control card, is a core component of an LED display. It receives image and video data from a computer serial port or DVI interface, stores frames in memory, and generates the serial display data and scan timing that the LED screen requires according to partitioned driving methods.
1. Control system classification
Asynchronous control systems
Also known as offline control systems or offline cards, asynchronous systems are mainly used to display text, symbols, graphics, or animations. Display content is prepared on a computer and preloaded into the display's frame memory via an RS232/485 serial port, then played back screen by screen in a loop. Main characteristics: simple operation, low cost, wide applicability.
Simple asynchronous systems can only show numeric clocks, text, and special characters. Graphic-text asynchronous systems add the ability to control display regions independently and support analog clocks, countdowns, images, tables, and animations. They also provide scheduled power on/off, temperature control, humidity control, and similar functions.
Synchronous control systems
Synchronous control systems are used for real-time display of video, graphics, and notifications, and are typical for indoor or outdoor full-color large screens. Their working method is similar to a computer monitor: they update at least 60 frames per second and map the image on the monitor to the LED display pixel-for-pixel. These systems usually support multiple gray levels and rich color display, suitable for multimedia advertising. Main characteristics: real-time performance, rich expression, more complex operation, and higher cost. A typical synchronous system consists of a sending card, receiving cards, and a DVI graphics card.
2. Control card types
There are many types of control cards and many manufacturers, such as Moser, Lingsingyu, Zhongqing, Yangbang, Yikuo, and Jinhang. Broadly, cards fall into three categories: full-color synchronous cards, asynchronous offline cards, and full-color video offline cards.
In recent years, market use of USB flash drive-based LED control cards has increased. These can use a serial port connection to a computer or a USB flash drive to transfer information, reducing the need for a dedicated PC and cabling. They commonly support analog clock display and scrolling borders.
C-type card (partition card, USB and serial dual-communication)
- Supports 4-scan, 8-scan, and 16-scan single- and dual-color indoor, outdoor, and semi-outdoor modules. One card can be configured for multiple uses.
- Supports scrolling borders and analog clock functions.
- Maximum controllable single-color pixels: 114,688; dual-color pixel count is half that. Built-in four T08 interfaces and four T12 interfaces, expandable to eight interfaces.
- Display functions: text, images, animations, Excel tables, time, temperature, countdown/count-up.
- Suitable for shop signs, poster screens, vehicle-mounted screens, and various other screen types.
- Includes screen-lock function and four groups of scheduled power on/off periods.
E-type card (time partition, USB and serial dual-communication)
- Supports 4-scan, 8-scan, and 16-scan for various single- and dual-color indoor, outdoor, and semi-outdoor modules.
- Maximum controllable single-color pixels: 40,960; dual-color pixel count is half that. Built-in three T08 interfaces and three T12 interfaces, expandable to eight interfaces.
- Display functions: text, images, animations, time, temperature, countdown/count-up.
- Suitable for shop signs, poster screens, vehicle-mounted screens, and other screen types.
- Includes screen-lock function and four groups of scheduled power on/off periods.
- Supports both serial communication and USB flash drive data entry.
- Supports one USB flash drive managing multiple displays for centralized multi-screen management.
G-type card (serial communication)
- Supports 4-scan, 8-scan, and 16-scan single- and dual-color indoor, outdoor, and semi-outdoor modules.
- Supports scrolling borders and analog clock functions.
- Maximum controllable single-color pixels: 114,688; dual-color pixel count is half that. Built-in four T08 interfaces and four T12 interfaces, expandable to eight interfaces.
F-type card (time partition, serial communication)
- Supports 4-scan, 8-scan, and 16-scan single- and dual-color indoor, outdoor, and semi-outdoor modules.
- Maximum controllable single-color pixels: 40,960; dual-color pixel count is half that. Built-in three T08 interfaces and three T12 interfaces, expandable to eight interfaces.
- Display functions: text, images, animations, time, temperature, countdown/count-up.
- Suitable for shop signs, poster screens, vehicle-mounted screens, and various other screen types.
- Includes screen-lock function and four groups of scheduled power on/off periods.
- Supports serial communication. Depending on needs, it can connect to a computer via serial port or use a USB flash drive to transfer information. Using a USB flash drive can eliminate the need for a dedicated PC and wiring.
3. Control system architecture
Array-based control systems for full-color LED displays consist of a master control board, multiple slave control boards, and several scan boards mounted inside display cabinets. Each cabinet effectively contains a complete control system, which improves overall reliability and display quality. This structure addresses issues such as low frame-switching frequency, insufficient gray levels, and poor color uniformity when playing video on high-end LED displays.
An expert committee organized by the science and technology bureau determined that the technology has reached a level leading in China and is comparable to international products.
The introduction of this generation of control systems further improved Yuanheng Optoelectronics' technical capabilities in panel control and refined display signal processing. After adopting the array-based system, frame-switching frequency can be increased from around 60 Hz to over 120 Hz, eliminating visible flicker and ripple. Gray levels for red, green, and blue can increase from 256 to 1024, improving color vividness and accuracy. Finally, using LDVS signal transmission minimizes signal loss, synchronizes display content across the entire screen, and reduces color inconsistencies.
