Patent ID: 7062358

Claim:
A method for diagnosing a flow system of components, the flow system having at least a status signal indicative of the status of a component, comprising the steps of: receiving said status signal in an instrumentation and control database; comparing said status signal with limit values; setting a status signal by generating: an alarm signal; an alarm, if the status signal is outside the range of the limit values; or an event; outputting said status signal from said instrumentation and control database; receiving said status signal in a diagnostic apparatus; storing said status signal in a data storage device; detecting at least one change in said status signal; controlling by means of a control unit said service function dependent on selectable or predetermined information; and starting by means of said control unit at least one service function generating status information based on said status signal and dependent on a functional model of said flow system and on a set of predetermined rules describing the relationship between components of said flow systems; wherein the step of generating status information comprises the steps of; searching for a cause to a changed alarm among the other functions in a network of said functional model, associated with alarm signals; indicating the alarm signal as secondary, if the alarm signal for a function is caused by another function in the network, otherwise indicating the alarm signal as primary; propagating causal effects to other functions in the network, if the alarm signal is indicated as primary; propagating alarm signals to connected functions of conditional relations, if the goal connected to the network has conditional relations; and repeating the step of searching for a cause to a changed alarm for each function where the alarm signals changes due to the propagation rules.