Rugged display here, computer somewhere over there

Products with display extenders allow computers to be placed as far away as possible from industrial displays while maintaining superior picture quality and speed.

Industrial process control requires technology solutions that enable businesses and manufacturers to get the job done in rough and tough environments. But sometimes, ruggedizing everything isn't the right answer. Nigel presents an example of how implementing display extenders can increase production efficiency and reduce system costs by allowing computers and displays to be placed in different areas.

Industrial manufacturers need high-quality monitors and touch-screen displays located throughout their factory floors. However, the computers that run these displays often cannot handle exposure to dust, water, humidity, chemicals, extreme temperatures, vibrations, and other conditions characteristic of harsh environments without substantial hardening. Rather than ruggedizing computers to provide all the control needed for these applications, industrial manufacturers seek a more cost-effective approach.

To address this need, companies such as Coca-Cola Enterprises, Georgia Pacific, General Mills, Pfizer, Proctor & Gamble, and Nestle have started using products with display extenders, which allow computers to be placed as far away as possible from industrial displays while maintaining superior picture quality and speed.

Covering the distance

Roswell, Georgia-based Hope Industrial Systems, Inc. incorporates Adder Corporation's AdderLink X Series X-2 Silver Dual-Access Keyboard, Video, Mouse (KVM) extenders (Figure 1) into its industrial flat-panel monitors and touch screens. The KVM extender allows an industrial monitor, keyboard, mouse, and serial touch screen to be positioned up to 1,000 feet away from the computer or server using a single CatX cable. The dual version enables computer access both locally and remotely.

The twisted pair cabling supported by the KVM extender (Cat 5 or higher) comprises four pairs of cables, three of which are used by the modules to convey RGB video signals to the remote video monitor. Because these three pairs have slightly different twist rates, the RGB video signals do not always arrive at precisely the same time.

This effect, which is visible as separate color shadows on high-contrast screen images, becomes apparent particularly when using higher screen resolutions and some types of Cat 5e cables.
KVM extenders provide internal skew adjustment that can help rectify this issue. The skew adjustment works by delaying or advancing the timing of RGB color signals so that they are all delivered to the monitor at the exact same time.

Hope Industrial Systems incorporates this function into its monitors by mating the extender to the monitor using one of the following three methods:

• Mounting the unit behind the panel near the monitor, creating a stand-alone product for use with panel mount displays

• Mounting the KVM extender in a modular sealed NEMA 4/4X/12 enclosure attached to the rear of the display, creating a rear mount KVM extender for use with universal mount displays

• Inserting the KVM extender into the pedestal where it is hidden, protected, and sealed to NEMA 4/4X/12 specifications, creating a pedestal mount KVM extender (Figure 2) for use with pedestal mount displays

The KVM extenders' compatibility with other computers and small form factor size allowed Hope Industrial Systems to integrate this technology into its product line.

"There are several advantages to using these products", remarks John McGraw, director of operations at Hope Industrial Systems. "The X-2 Silver KVM extender provides a rugged metal industrial enclosure and allows for skew adjustment so that our customers can fine-tune pictures up to 1,000 feet away. These clean, sharp pictures can withstand factory electromagnetic interference, which is an important feature in this business".

Small, fast, and seamless video extension

McGraw says the company has received positive feedback from customers who report excellent picture quality, long-term reliability, continually updated software, and substantial cost savings as a result of not needing to purchase rugged computer equipment.

Other industrial manufacturers have noted similar benefits. Controls engineers at Coca-Cola Enterprises state that these extenders are so small, fast, and seamless that they can't tell the video is being extended. This efficiency enables technical staff at General Mills Canada Corporation's plant to put their computers in a dry area and touch screens in wet areas.

Besides the KVM extenders for standard serial devices, Hope Industrial Systems plans to possibly integrate Adder's KVM extenders for USB devices into its products in the near future.

Nigel Dickens is CTO for Adder Corporation in Newburyport, Massachusetts, where he has spearheaded a range of innovative product developments since 1991. With more than 20 years of experience in the electronics industry, he is a Chartered Engineer and a graduate in Electronics from Cambridge University.