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Fault detection, isolation, and recovery (FDIR) is a subfield of control engineering which concerns itself with monitoring a system, identifying when a fault has occurred, and pinpointing the type of fault and its location. Two approaches can be distinguished: A direct pattern recognition of sensor readings that indicate a fault and an analysis ...
Fault reporting is a maintenance concept that increases operational availability and that reduces operating cost by three mechanisms: Reduce labor-intensive diagnostic evaluation; Eliminate diagnostic testing down-time; Provide notification to management for degraded operation; That is a prerequisite for condition-based maintenance. [1]
In the nominal, i.e. fault-free situation, the lower control loop operates to meet the control goals. The fault-detection (FDI) module monitors the closed-loop system to detect and isolate faults. The fault estimate is passed to the reconfiguration block, which modifies the control loop to reach the control goals in spite of the fault.
Automatic correction is possible for redundant systems when fault-detection, fault-isolation, and fault-bypass are all automatic. Automatic corrective action is also called Active Recovery and Self Healing. This technique can be used to increase the MTBF to the length of time an item will be required to be used without maintenance.
graph with an example of steps in a failure mode and effects analysis. Failure mode and effects analysis (FMEA; often written with "failure modes" in plural) is the process of reviewing as many components, assemblies, and subsystems as possible to identify potential failure modes in a system and their causes and effects.
This is usually handled with a separate "automated fault-detection system". In the case of the tire, an air pressure monitor detects the loss of pressure and notifies the driver. The alternative is a "manual fault-detection system", such as manually inspecting all tires at each stop. Interference with fault detection in another component.
The impact of any latent fault tests, and The operational profile (environmental stress factors). Given a component database calibrated with field failure data that is reasonably accurate, [ 1 ] the method can predict device level failure rate per failure mode, useful life, automatic diagnostic effectiveness, and latent fault test effectiveness ...
Watchdog timers are sometimes used to trigger the recording of system state information—which may be useful during fault recovery [4] —or debug information (which may be useful for determining the cause of the fault) onto a persistent medium. In such cases, a second timer—which is started when the first timer elapses—is typically used ...