Take a second look at screen displays

Daniel Quitzau, who is responsible for large screen display solutions at Mitsubishi Electric Scandinavia,examines how display technology has evolved and where we might be headed in the future:

Sollentuna, Sweden - The sight of a control room with a big screen display is quite a familiar one for anyone involved in process control activities in the petrochemical or utilities industries. Yet, while the outward appearance might be a familiar, the technology – and indeed the purpose – of large screen displays has been undergoing a quiet revolution over the last decade.

That revolution is called Command, Control, Communications and Intelligence, or C3i for short: Borrowed from the US military, the term C3i is now used extensively in process control applications to describe an integrated system of procedures, facilities, software and hardware that allows effective decision making, planning and the real-time control of activities.

Central to the idea of C3i is the ability to access and visualise data. In industry, the list of system components - valves, drives, solenoids and sensors – that are network-able grows longer year by year. This is in addition to CCTV cameras, videoconferencing and offline data sources, all of which are vital to the effective operation of a C3i facility.

Ironically, while the growth of networked devices has given system designers access to every last detail of process data, the information overload that can easily result can often cause more problems than it solves for operators and managers. Consequently, the question which occupies the attentions of system integrators now is not so much how to access data, but how to use it effectively. The display wall is central to that ability.

With the massive rise in the volume of data that must be managed, the function of a central control room display has had to evolve, technically and conceptually, far beyond that of being just a large video screen; Conceptually, the modern display is now required to operate as a digital workspace in a very real sense, allowing everyone to be aware of not just their own sphere of responsibility, but also how it relates to others.

Technically, a display system must provide the ability to effortlessly drill down to a particular piece of data, or zoom out to take in the overall picture on demand. This ability to present data at just the right level of detail for a given task is essential in being able to manage the tide of information flowing into a typical C3i facility.

In the early days of control rooms, data visualisation was typically provided by a videowall – a collection of “cubes”, each containing a video projector aimed at a built-in screen surface. In today’s C3i facility, the same principle is still used, but any outward similarity a modern display wall system has to the videowall of yesterday is really only skin-deep.

Technical demands have proved a strong driver of display technology, powering the transformation of rear-projection over the last decade from low-resolution videowalls to today’s sophisticated collaborative data platforms. The biggest single factor in that development was the arrival of the DLP chip. Developed by Texas Instruments, DLP or Digital Light Processing, has revolutionised rear-projection data display, and forms the basis for all Mitsubishi Electric projection cube displays.

The chip surface is made up of 1.4 million microscopic moving mirrors, which direct light from a powerful lamp onto the screen in one position, and away from the screen in the other. Incredible as the idea of a million tiny wiggling mirrors sounds, DLP has proved a completely reliable technology, enabling a new generation of screens that are brighter, have far greater colour conformity, longer life-spans and far more efficient and effective than the old video projectors they replaced.

One of the key requirements in C3i applications is the accuracy of colour reproduction. Much of the information displayed in process control is colour coded; If you are expecting operators to act based on the information they see, it’s obviously hugely important that they can clearly distinguish between colours such as yellow and orange. Colour accuracy is such an important aspect of display cube design that Mitsubishi Electric has focused considerable effort on developing extremely accurate colour reproduction in its display products.

Colour Space Control works together with another Mitsubishi innovation, Dynamic Brightness Balancing, to create a display screen that effectively monitors and adjusts itself so that it is always delivering optimal performance. Display uniformity and accurate line-up of the individual modules is also hugely important. Misaligned images and differences in colour and brightness has been shown to be a major factor in operator fatigue and misinterpretation of displayed information.

Equipment reliability and cost of ownership have also become extremely important issues. Again, the advent of DLP technology has made a big difference. The old-style control room displays based on videowall projection had a number of limitations. Top of the list was a phenomenon known as “phosphor burn” or “image sticking”. A static image displayed continuously on a TV screen will eventually burn itself into the screen surface creating a ghosting effect that renders it unusable. Failure of high voltage components was also common, causing sudden - and occasionally spectacular – flashover damage to other parts of the projector. Problems of this kind required frequent part replacement, causing high downtime and high cost of ownership.

DLP is completely immune to such problems. In a recent control room refurbishment project where video-based displays were replaced by Mitsubishi DLP units, the entire cost of the renovation was recouped in less than 18 months through savings in repair costs alone. Mitsubishi displays can also be supplied with options such as automatic lamp changers, which will not only physically replace a failed lamp automatically with 10 seconds, but also adjust the colour performance to compensate for the characteristics of the new lamp. The idea is to ensure 100% up-time and continuous 24/7 operation.

DLP technology has made projectors lighter and more compact, and this means they can usually be retrofitted easily into existing facilities. Greater efficiency means that running costs are reduced, but also those of the associated infrastructure costs such as air handling. The reduced footprint means that the display takes up less floorspace, and features such as the front-access versions of Mitsubishi’s 50” and 67” cubes allows displays to be fitted directly against a wall.

Great progress has also been made in the processing driving the display wall. A typical C3i facility will manage a very diverse number of inputs, including CCTV cameras, videoconference feeds, off-air broadcasts and multiple data sources a well as process data. These inputs will be managed by a sophisticated outboard processor, which can be programmed to present just the right amount of information on demand. The complexity of the data management is hidden from the operator, who just sees the information they require to perform a particular task. A recent installation in St. Petersburg, for example, mixes live telemetry with video and information derived from several different databases, and presents them to the operator in a series of layers which can be turned on and off on demand.

The most recent developments have been in the ability of information to be visualised in different ways, such as larger LCD panels which can be used in a C3i environment as a group workstation and higher resolution products that enable a group of operators to examine a particular section of the display in precise detail, with no loss of resolution.

Looking further into the future, Mitsubishi Electric in Kyoto recently revealed a 7.5m diameter circular display based on 67" Display wall cubes. Using special image processing, the 340 degree, two-metre high display allows the viewer to be completely surrounded by the display image. There are some interesting commercial applications for this kind of immersive display technology, particularly where a process spread over a wide geographic area needs to be visualised

Quality is arguably more critical in C3i than any other display application, and we believe delivering quality is not just about hardware, or software - and it’s certainly not just about cost. Quality comes from expertise, and expertise is very rarely available from an off-the-shelf solution. In today’s mission critical, technology-heavy C3i applications it is more vital than ever that customers choose their suppliers and partners carefully for their expertise, not just in display technologies, but a wide variety of data management and network disciplines.