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2.1 Preliminaries
State-of-the-Practice
Fault diagnosis at PMS
Figure 2.1: Philips Cardio-Vascular X-Ray System
2.1.2 Introduction of the Power Supply Example
This section introduces an example that is used throughout this thesis for clarifying fault diagnosis
related concepts and ideas. The Cardio-Vascular X-Ray System is a complex system that has
dozens of components. Consequently, the power supply of all electrical components has quite some
complexity. Figure 2.2 partially shows the architecture of the system in respect to the power supply.
The idea is to keep it simple, and therefore it is not complete in its depicted components. On the
left, the most important power supply of the Cardio-Vascular X-Ray System, the so-called Power
Distribution Unit, is shown. Its function is to switch on the various subsystems by supplying voltage
(230V). The components on the right (Flat Detector, TBCB, CRCB, Collimator, Chiller) are all
components that need voltage. Their behavior is beyond the scope of this thesis. The function of
the component in between, the chameleon, is to provide part of the components with low voltages
(24V).
From now on, this example is referred to as the power supply example. The power supply example
is used in Chapter 3 for introducing various automated approaches to fault diagnosis. Chapter 4
uses it to show a realistic example of model-based diagnosis applied to the Philips Cardio-Vascular
X-Ray System. The following preliminary section also uses the power supply example in order to
introduce some fault diagnosis related concepts.
2.1.3 Faults, Errors and Failures
The previous section introduced a subsystem of the Philips Cardio-Vascular X-Ray System. Notice
that the term subsystem refers to a subset of interrelated components within the X-ray system, and
not to the subsystem decomposition as defined in the system design document [16] of the X-Ray
System. This section uses power supply example to introduce notions related to fault diagnosis.
Fault diagnosis is a mean to deal with the threats to a dependable operation; faults, errors and
failures. It is important that the reader fully understands these concepts, because these are part of
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