| Flightdeck-UI Server, Network and Industrial Process Monitoring | ||
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Flightdeck-UI, being modeled along the lines of aircraft cockpit design [Lon01], is very well suited as a monitoring interface. The current version focuses on a variety of virtual analog instruments to display output for the user.
While annunciator features (see below) are present in Flightdeck-UI, and more are planned for the future, the augmentation with other types of virtual instrumentation is very important to the user's ultimate experience — particularly for the reduction in operator error. In contrast, common monitoring tools tend to use a pure annunciator model. The Flightdeck-UI approach gives much greater situational awareness to the user, as described in this chapter. For more information on the general ideas and design of Flightdeck-UI, see the Flightdeck-UI whitepaper [Bel03].
Annunciator-style readouts are common in both everyday life and in mission critical applications. The alarm clock and the traffic light are familiar examples. Automobiles have various warning lights in the dashboard, to indicate low oil pressure, problems with the engine control system, etc. A good example from aircraft instrumentation are the 3 lights that turn green when the landing gear is properly extended.
Annunciators are a very compact way to provide information, but they suffer from a number of limiting factors. The major difficulty is that annunciators give no warning of marginal performance. Everything looks fine, and then suddenly there is a problem. In many situations, it is thus undesirable or even impossible to rely on annunciator-style displays entirely.
Another problem with annunciators is defining the events that trigger them. In the simplest cases, this involves setting some kind of a threshold. More complex designs require the configuration of multiple parameters to a mathematical or logic function. In any case, the wrong setting can cause the annunciator to signal a false warning, to signal too late, or to fail to signal at all.
Finally, a triggered annunciator gives no indication of the scope of the problem. This is one of the reasons why drivers run red lights. Even with the extra protection that a yellow light affords, there is no accurate indication of how soon the red light will actually appear. A driver who is momentarily distracted, or is not familiar with the intersection, has a difficult decision to make. The wrong choice can mean a traffic ticket — or worse. Stopping is not always the safe choice it is promoted to be, as sudden braking can lead to skids or rear-end collisions.
Some faults can also trigger a number of annunciators at once, leading to confusion. The confusion is greatly exacerbated by the limited amount of information provided by each annunciator, in addition to the information overload of many activated annunciators (this situation is rather like taking coffee in an attempt to counteract the effect of too much alcohol).
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| Introduction | The Pure Annunciator Model |