Business Overview

Business introduction

The Fault State DEX deals with how a product can or may degrade in its functions or change the value of its properties. It is usual for the set of fault states to be derived from a formal analysis process such as Failure Modes and Effects Analysis (FMEA).

A set of basic definitions:

a failure is the termination of ability to perform a required function (i.e. failure is an event);
a fault is the state of an item characterized by inability to perform a required function;
a fault state is the consequence of a failure;
a failure mode is a sequence of events which lead to a particular fault state.

The information exchanged by this Dex is the set of "potential faults and relationships" produced as a result of the PLCS AAM activity A2224 "define potential faults".

NOTE The product functions may be represented by a functional_breakdown. Faults may be defined using the state_definition module.

EXAMPLE A bicycle has a breaking function. During a ride one could detect that the ability to decelerate or stop the bicycle as needed is no longer available, hence a failure has occurred. The bike is then in a fault state. There could be more than one sequence of events leading to this fault state. These are known as failure modes. Possible examples of failure modes are broken break cable or break block worn beyond limits.

Figure 1 — State of a product over time

Business process

This exchange enables the transmission of the data exchange set (DEX) Fault States

The Fault State Dex deals with how a product can or may degrade in its functions. It is usual for the set of fault states to be derived from a formal analysis process such as Failure Modes and Effects and Criticality Analysis (FMECA)

The analysis is an iterative process, potentially changing at each stage of the products life cycle. The initial analysis ideally conducted as early as possible in the product life cycle.

The formal analysis, such as FMECA, is conducted with the following objectives:

Feedback of required changes to design;
Evidence of safety and reliability have been given due consideration in the product design;
Identification of support drivers, which are the justification for the generation of maintenance task descriptions.