Abstract: The present invention refers to an apparatus, a method and a computer program product for modelling causality in a flow system, and more specifically for modelling variable causality in the flow system. The apparatus 100 comprises a data storage means 110 configured to store model element data related to modelled components of the flow system, a causal rule storage means 120 configured to store a plurality of causal relations determining the causal relationships between model elements. The apparatus 100 comprises a state determination unit 130 arranged to receive a status signal from the flow system, identify the component related to the received status signal, identify a model element modelling the identified component and determine an operating state of the identified component. Further, the apparatus comprises a processing means 140 configured to activate or deactivate a causal relation related to the identified model element and dependent on the determined operating state.

Abstract: The present invention deals with diagnosing of a flow system, using status signals carrying information about said flow system, whereby new status information is generated, which relates to a plurality of aspects of the flow system based on said status signals and dependent on a functional model and on a set of predetermined rules. The invention comprises a diagnostic apparatus (20) arranged to analyze the status signals for example by means of an alarm analyzer (23a) arranged to separate alarms into primary and secondary alarms, a sensor fault detector (23b) arranged to detect sensor values that probably are wrong or a fault diagnozer (23c) arranged to find the root causes for unfulfilled goals. Further the invention can comprise a failure mode analyzer (23d) arranged to detect functions that can stop working in the future or a process measurement analyzer (23e) arranged to analyze the status signals of a specific process.