In this document, detailed information about both the hardware and the product software-based regarding the led wall will be given. You can access information under the following headings in general:
Led Wall Unit Scales: Generally, the components in a led wall unit will be explained such as cabinet, led module.
Sending Card and Screen Connection: In this section, information such as how it works about Sending Card will be given. Additionally, Novastar solutions will be explained.
Led Wall Cabinet: In this section, the following will be mentioned; receiving card and receiving card solutions, hub board, notification board, power supply, output, and input ports.
Led Wall Calibration: Under this heading, questions such as how to calibrate the led wall, what are the calibration types will be answered.
Led Wall Unit Scales
Generally, communication from the most basic to the root level is Screen >> Cabinet >> Led Module >> Data Group. As seen in Figure 1, there is a 5m screen of 2000px. It can also be seen that 1 cabinet contains 2×2 Led Module, Led Module contains 2×4 Data groups, and Data Group has 4LED Drivers x 7 MOSFETs.
Figure 1: Led Wall Unit Scales
Simply, as shown in Figure 2, Content Source / Controller Unit is connected to the sending card, and sending card is connected to the display via the Ethernet interface.
Figure 2: Architecture Sample
Sending Card and Screen Connections
Media input is splitted and adressed to each cabinet that corresponds to receiving card. Distribution is carried out over ethernet. Each Sending Card has its input and output capacity depending on its FPGA module. You can see an example sending card in Figure 3.
Figure 3: Sending Card Sample
You can access all solutions of Novastar company from the table in Figure 4. Additionally, you can check their technical details.
Figure 4: Sending Card Solutions
The cabinets are connected together to build LED WALL as shown in Figure 5. External Sending Card is used to split and transmit video data to cabinets via Ethernet cables.
Figure 5: Screen Connections
Note: Maximum P2.5 Cabinet Quantity connected over every single Ethernet Port of MCTRL600 Sending Card (@8bit): 15
Maximum P2.5 Cabinet Quantity connected over every single Main Power Cable: 15
You can check the ethernet port’s input/outputs and how cabinets are connected in Figure 6.
Figure 6: Ethernet Port Inputs and Connection Structure between Cabinets
Led Wall Cabinets
LED-Wall is a display solution in which cabinets are tied up together side by side to obtain a screen in desired size and resolution. Each cabinet has 4 types of boards: Receiving Card, Hub Board ,Notification Board and LED Board (4 pieces.
You can see Figure 7 for the architecture, internal structure and front view of a cabinet.
Figure 7: Cabinet Structure – Inside of Cabinet – Front View
Receiving Card
Basically receives its part of image data, converted according to LED Driver Configuration of system and divided to data groups. Additionally, you can check receiving card out left side of Figure 8. In the right side, you can also see the location of the receving card in the system.
Figure 8: Receiving Card and Architecture
You can access all receiving card solutions of Novastar company from the table in Figure 9. Additionally, you can check their technical details.
Figure 9: Novastar Receiving Card Solutions
Hub Boards
Basically, Hub Board has 4 functions;
- Get video data from the input port of the cabinet and transmit it to the receiving card
- Transfer data from receiving the card to LED Boards via 4 connectors
- Test button to start internal test pattern
- Connector to provide status information over Notification Board
Please check Figure 10 for Connectors and Test Button. There are Top Placement image and Bottom Placement image respectively.
Figure 10: Hub Boards Top-Bottom Placement
Notification Board
Notification board provides status information of the receiving card over 2 LEDs(red and Green). You can see the indicators, their status, and their description in the table in Figure 11.
Figure 11: Notification Board Status and Description
Led Board
Led Board, is the primary part of the Cabinet, on which the RGB LEDs are taking place. In our current solution, every cabinet has 4 LED Boards. The bottom side of LED board has drivers, power switches, and a connector for connection with Hub Board. You can check Top and Bottom side of LED board from Figure 12.
Figure 12: Top-Bottom side of LED Board
Led Wall Cabinet – Output and Input Ports
Every cabinet has one input and one output Ethernet port. as shown in Figure 13. Input port is used to get video data from Sending Card and output port is used to transfer this data to next cabinet. Also every cabinet has 2 power ports: Input and output to bridge 220V AC to next cabinet.
Figure 13: Input and Output Ports
LED Wall Calibration
Brightness/Color uniformity is one of the most important factors that affect the image quality of a full-color LED display. Because of the limitations of the manufacturing process, including system structure design, LED lights selection, electronic components welding, system cooling, LED brightness decaying, and many others, LED displays to suffer the brightness/color uniformity loss.
A calibration tool performs brightness/color adjustment to the display after it has been completely produced by adjusting the brightness/color of each LED light according to the software analytical results from the measured brightness/color values of the LED lights.
Figure 14: Calibration Effect
Calibration Types
- Cabinet Calibration: Each Cabinet must be calibrated in the factory before shipment
- Led Wall Full Screen Calibration: Optional full-screen calibration may be done after installation
Figure 15: Calibration Process