Comparison of LVDS and RGB interfaces in industrial computers

Interfaces make it possible to transfer images from devices providing data such as industrial computers to devices presenting data, e.g., displays. Without an interface, the two devices could not work together. In today’s post, we will compare LVDS and RGB interfaces. What are their biggest advantages? What types of interfaces can be found in Unisystem’s offer? In which industries are they used? 

What is an industrial computer?

Industrial computers are specialised devices designed to operate in demanding industrial environments where ordinary computers would not be able to function reliably. The design of industrial computers is resistant to a variety of factors, such as extreme low or high temperatures, moisture, dust, vibration or electromagnetic interference. 

Industrial computers are designed for continuous 24/7 operation and feature industrial-grade components that are more durable than those used in consumer computers. They can also be adapted for installation in various configurations such as control cabinets or directly on production lines where integration with machine control systems is required. An important feature of industrial computers is also their ability to operate in real time, allowing precise management of production processes. 

For this reason, they are important components in industrial automation systems where operational reliability is a priority. As a result, industrial computers can be used to, e.g., monitor production processes, collect data from sensors, control machines or robots, control production parameters and support the operation of human-machine interfaces (HMI, Human-Machine Interface), which ensure smooth and efficient industrial processes. 

LVDS and RGB interfaces in industrial computers

Interfaces can be divided into two groups: internal solutions and external solutions. In the first case, they are used to directly connect components mounted in the same device, while in the second case, they are used to connect two separate devices. LVDS and RGB interfaces are internal solutions. 

In recent years, RGB and LVDS interfaces have been most commonly used in LCD-TFTs. A few years ago, you could read in the manuals that the choice between RGB and LVDS interfaces depended on the resolution of the LCD-TFT. At the time, the RGB interface was recommended for resolutions below 640×480 and LVDS for resolutions above 800×480. However, developments in technology have changed these boundaries. Today, the RGB interface is used for resolutions lower than 1280×800 px and LVDS for resolutions higher than 320×240 px. It is worth mentioning that modern microprocessors and microcontrollers often have a built-in RGB and/or LVDS controller, which greatly simplifies the implementation of LCD-TFTs in end devices. 

LVDS – what is it? How does the LVDS interface work?

The main task of the LVDS (Low Voltage Differential Signalling) interface is the transmission of images. The solution requires four differential pairs, of which one is for clock transmission and the other three for data transmission. The LVDS interface operates in unidirectional mode, transmitting data serially, which means that the bits are transmitted one after the other. The signals are transmitted as voltage differences on the wires, and the conversion takes place at the receiver side. The LVDS interface offers three modes of data synchronization – VSYNC, HSYNC and DE.

The greatest advantages of the LVDS interface are its high bandwidth, low electromagnetic interference emissions and the ability to transmit data over long distances without loss of signal quality. In addition, the low voltage level used in transmission makes the aforementioned interface energy-efficient. It is worth mentioning that the LVDS interface is commonly used in point-to-point configurations, which enables fast and reliable data transmission between the transmitter and receiver. Unisystem offers standard and wide-format LCD-TFTs with LVDS interface. 

Industrial computer with RGB. RGB interface principle

The RGB (Red Green Blue) interface is a technology that transmits data in parallel, using multiple wires simultaneously. Each wire transmits single-bit information, which is responsible for the intensity of the red, green or blue colour for each pixel. Depending on the version of the interface, the number of wires can vary, e.g. a 24-bit version requires 24 wires for each pixel. Different signals are used in the RGB interface to synchronize the display of the pixels and also to ensure that the data transmission is correct. Despite the high bandwidth, which can be up to 1.2 Gbit/s, this interface requires a large number of wires, which can result in higher levels of electromagnetic interference. 

RGB interfaces support five types of signals: VSYNC, HSYNC, DO…DDX, DCLK, DE. The greatest advantages of the RGB interface are its simplicity, directness in data transmission and high image quality. Because the RGB interface transmits data in parallel, it is able to quickly provide colour information for each pixel, resulting in high resolution and accurate colour reproduction. 

Application of LVDS and RGB interfaces in various industries

Both LVDS and RGB interfaces are commonly used in industrial solutions. They can be found in, e.g.: 

• manufacturing industries, e.g., in industrial controllers supporting the automation of production processes, 
• commerce, e.g., POS (Point of Sale) systems, 
• transportation, where they are used in passenger information systems,
• digital signage solutions, 
• medical devices, 
• the automotive industry, where they are used to create multimedia and navigation systems. 

LVDS and RGB interfaces are also used in consumer electronics – they are used in TVs, monitors, scanners, digital cameras and all other digital and analogue devices that analyse images. 

Performance differences between LVDS and RGB interfaces

The main differences between LVDS and RGB interfaces in industrial computers are shown in the table below:

Check out the variants of industrial computers available from Unisystem. 

If you’re looking for an industrial computer for a device you’re designing, contact us – together we’re sure to find the right equipment, performing well even in the toughest environments.