Control Systems for Electronic Displays and Networks

July 12, 2005

By Teri Ronning

Control is everything. Clients recognize that investing in high-quality LED video displays is crucial, yet some fail to recognize that the right control system is what enables the LED display to look truly dynamic and offer flexible programming options. Specifying the ideal control equipment ensures that clients can produce quality messages and broadcasts efficiently and effectively.

Planning an intricate control system requires attention from control room designers and architects. Working together, they address the space needed for the equipment, the type of information that the customer wishes to display, and the staff size that a system will require - all while fitting within the budget.

Selecting suitable gear begins with identifying what the customer expects to accomplish. Some clients have elaborate visions, with multiple video feeds, intricate animations, dynamic data, and impressive sound shows. Others simply desire a basic system with simple text messages and still images. To fulfill the client’s needs, it’s essential to know the range of control system capabilities and how to go about creating a control system that meets the client’s expectations.

Control rooms for live events can become quite complex, with intricate LED systems using from three to 18 operators. For example, a live event control room needs one person for each camera, one to two camera grips handling cables, an engineer, a technical director, a director, a producer, a slow-motion operator, a tape operator, and a utility person. Some facilities combine jobs to reduce costs; others increase staffing.

On the other hand, a basic system, such as that found, for example, in an auto dealership, requires only one operator to create and schedule messages. After the initial setup, the operator simply edits the schedule and loads new messages.

I. The Basic System

Many businesses or organizations use displays for sales promotions or brand identity. These types of clients usually need just a basic system, with a controller to provide messages, scheduling and content delivery, and an optional video processor for video feeds.

Creating content

When selecting a system integrator of control technologies, start by evaluating the functions and capabilities of the video display controller the provider is proposing. Most manufacturers provide controllers that create graphic and text messages. When comparing controllers, note the type of graphic files it imports, such as AVIs (animations), BMPs (bitmaps), JPEGs, TIFFs, etc.

Animations are popular for LED message displays. However, to display animations properly, the controller must run at approximately 30 frames per second for the motion to appear fluid. While some controllers include applications to create basic animations, users typically create animated messages in far more sophisticated third-party design programs, such as Adobe’s AfterEffects or PhotoShop, and then import the messages into the controller. The controller, therefore, must be compatible with the design programs from which the animations will originate.

Live data, another popular feature, can include anything from time and temperatures to market information. Many clients choose to subscribe to services offering news, stock quotes, or even the latest sports scores. Initially, the systems contractor who installs the control technology arranges for the delivery of such content over the Internet. But after the initial contract period, customers are generally responsible for renewing subscriptions or finding new sources.

Customers who want to display video images will need a video processor, which transmits compatible video signals from either a live video feed or a Digital Disc Recorder (DDR), Video Tape Recorder (VTR), or a Digital Video Disc (DVD) player on which previously produced information is stored.

Schedules & Logs

After the messages have been designed and saved as digital files, they are transmitted from the controller to a single display or to a display network. Scheduling makes it easy for a single operator to manage thousands of messages by adjusting the start and stop time, as well as the first and last play date of each message file. Some controllers can create file rotation schedules, and some offer advanced programming for scheduling displays to blank, brighten, or dim at various times or under certain conditions. Another feature, advertisement logging, generates reports of ads displayed. A controller that can generate reports internally reduces overall costs by eliminating the need for additional software.

Delivering content & Messages

Most display systems deliver content in one of three ways: to a single local display, to multiple networked displays, or to remote displays.

All that is needed for a single display is a cable that connects the controller to the display. But many clients require centralized control of multiple displays, which is far more complicated. For example, a sports arena’s displays are often located throughout the facility. The main scoreboard, digital advertising displays, and concourse displays each provide different content, ranging from game statistics to league scores, advertising messages, and snack bar specials.

There are several ways for delivering content to displays. For a facility using the displays to play back predetermined content, users often choose to send the information over an existing network to the display. Applications that require instant control of displays, such as a sporting venue, need a higher bandwidth for transmitting information. In this scenario, customers use fiber-optic cable to deliver content from the controller(s) to the respective displays.

As technology advances, an increasing number of users desire one command center for multiple displays located either in the same city or across the country. Classic examples are found in New York’s Times Square, where remotely controlled displays receive information from controllers in remote office buildings. The controller sends messages and schedules over Internet or wireless connections to a remote player located at the display site, which then relays information to the display.


To maximize display uptime and reduce maintenance expenses, the most intelligent LED display controllers incorporate diagnostics to proactively monitor display operations, giving owners reassurance their display system is functioning properly. The diagnostic features depend on the manufacturer and can include anything from warnings that a power supply may overheat to the latest firmware revisions. If adverse situations arise, the controller automatically alerts appropriate personnel and provides critical information to aid in servicing the display.


The best manufacturers of display equipment incorporate field calibration, which enables the operator to ensure that the LED video display looks “factory fresh.” LED displays succumb to intensity degradation over time. Each LED, having a unique personality, slowly degrades at a different rate, causing an uneven or patchy image. After calibration instruments read the intensity of the display, the display controller restores LEDs to a uniform level.

II. The Advanced System

While displaying basic animations and prerecorded video satisfies some customers, other clients’ needs go deeper and are more complex. Many advanced models used in sporting venues and high-profile commercial applications, for example, include video processors and front-end video equipment.

Video Processor

Video processors provide an interface between controllers, front-end video equipment, and displays, enabling operators to control the format and enhancement of the video signal. This is an essential element for LED displays, because the preferred signal input is often proprietary. The video processor converts a standard broadcast signal to the signal used by the controller or display manufacturer.


With the digital craze sweeping the electronic industry, most equipment today accepts both analog and digital signals. Digital signals provide the best picture possible, in part because analog signals, a much older technology, are far more vulnerable to noise. Nevertheless, until the industry switchover is complete - scheduled for 2006 - the video processor should accept both signal types.

Digital signals typically are produced in one of two formats: standard-definition television (SDTV) and high-definition television (HDTV). The SDTV standard consists of 480 vertical lines and 640 horizontal lines interlaced (i) and a 4:3 aspect ratio. Interlaced scanning shows odd lines followed by even lines during the second scan. With 30 frames shown per second, the interlaced format shows one-half of the frame every 60th of a second. The most superior HDTV signal uses a 1080i and 720p (progressive) format in a 16:9 aspect ratio. The progressive format shows the entire picture at once, every 60th of a second.


Most video processors can display multiple video sources at one time - four inputs is ideal. In many cases, up to three SDI (serial digital interface) inputs or HD-SDI (high-definition serial digital interface) inputs can display simultaneously. The sources may be a variety of devices with digital output, including cameras, decks, switchers, and DDRs.

For analog users, video processors should accept four analog video sources through composite, component, and S-Video connections. A connector can hook up a maximum of one component and composite signal or four composite signals.

Occasionally, customers require more inputs than a video processor accepts. Experts then recommend chaining additional processors together.

Frame Rates

To provide a lower-cost system, some video providers reduce the speed that the display is repainted, or ‘refreshed.’ To provide the smoothest video image, the LED display should support 60 frames per second.

Additional Features

Most video processors provide additional image correction features to portray the best image. Basic features include image adjustment to prevent motion blurring, smoothing edges of diagonal patterns, reducing noise, and sharpening images. Users also may create display zones to portray separate content on one screen, similar to the picture-in-a-picture feature on a television set. Finally, a video processor should switch from one input to another seamlessly to create a professional polish for video presentations.

Front-End Video Equipment

Dynamic front-end video equipment empowers users to present vibrant content using live video and clips, graphics, animation, and overlays. The gear that will be needed depends on the content desired. Playback of pretaped content, instant replay, or live video are the most common.

The most basic system provides just a character generator, allowing operators to display text, graphics, and live data over background images or live video. An example of character-generated content includes a network bug or a player bio.

Many front-end video systems include servers to store video clips. This valuable feature allows customers to review clips at the computer, rather than storing to tape or DVD. The best manufacturers offer about 20 hours of storage.

Other important options to consider are the number of video inputs and outputs. Inputs and outputs accept camera feeds, as well as switchers. If the front-end video system contains these inputs, the need for additional inputs on the video processor lessens. For example, if four cameras hook to the front-end video system, a single cable containing information from all four of the cameras feeds into the video processor.

Additional equipment provided within LED control rooms may vary, depending on the client’s requirements. Everything should integrate with controllers and front-end video equipment. Common auxiliary tools include VTRs, DVD players, A/V switchers, and audio equipment. Cameras are also a critical component. Industry experts recommend purchasing an electronic field production (EFP) camera system.

Network Security

Security is crucial - especially in control rooms that have access to the Internet. Experts recommend taking the following precautions to ensure a safe and reliable network.

  1. Ensure the operating system is current. Schedule the computer to automatically install all necessary updates.
  2. Purchase antivirus software and update often, daily if possible, weekly at a minimum.
  3. Install a firewall on all computers with Internet access to protect the computers from external threats. Not all computer viruses arrive through e-mail. Viruses infect computers on unprotected connections as well.
  4. Confirm that the network computers run only essential services. If network computers don’t need to share files, disable the ability to reduce the chance of a virus or worm.
  5. Establish passwords to limit physical access to control equipment to just those personnel who are running, repairing, or maintaining it.

Teri Ronning is a member of the Daktronics video products marketing group. A graduate of the University of South Dakota, she holds a bachelor of science degree in journalism and a master’s degree in administrative studies.

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