Patent ID: 6226760
Filing Date: 2001-05-01
Classification: G07C

Abstract:
A fault diagnostic apparatus having a diagnosis module for detection of defective components of a technical system characterized by fault-relevant process variables, a condition of which changes, upon an occurrence of a particular component fault, from a no-fault condition to a fault condition in that a condition value departs from a given tolerance, said diagnosis module comprising:a memory;a checklist stored in said memory; anda table of conditions stored in said memory; whereinthe checklist and table of conditions are predetermined via fault simulation in a generated operational model of the technical system, during which the fault-relevant process variables are determined separately for a particular defective system component, based on primary process variables which depart from a given tolerance due to an occurrence of the fault in the particular defective system component, and on secondary process variables affected by the primary process variables;the checklist provides a partial checklist for each primary process variable, which partial checklist indicates the secondary process variables, that are affected by the primary process variable;the table of conditions identifies, for every combination of conditions, corresponding system components suspected of defects;while the technical system is running the diagnosis module detects current condition values of the primary process variables, determines a condition of the current condition values based on primary process variables, and upon detection of a defective condition for one of the primary process variables, activates a diagnostic process in which it acquires from the checklist secondary process variables corresponding to a primary process variable in a fault condition; andthe diagnosis module uses condition values of the secondary process variables from the technical system to obtain their present condition, compares a first combination of conditions of the fault-relevant process variables with a second combination of conditions stored in the table of conditions, and if the first combination of conditions matches the second combination of conditions stored in the table of conditions, identifies a suspected system component correspondingly stored in the table of conditions.