Legal information

Copyright DB Netz AG, licensed under CC-BY SA 3.0 DE (see full text in CC-BY-SA-3.0-DE)

ARCH.053 Create initial system functional chains

Goal

Define the sequence and decision logic of system functionality needed to achieve a system capability in a format that is usable for failure mode analysis.

Requirements met by this process step

ISO 15288 6.4.3.3 b 1)
EN 50126-1 7.3.2.1 a), d), e), 7.5.2

Inputs

AMOD-138 Single system capability context

Knowledge of workshop participants (optional)

Functional chains from collaborative projects (optional)

OutputsAMOD-059 Initial system functional chain description
Methodology

If the person creating the output view knows enough about how the system works with the actors for this capability, they can create the functional chain description diagram directly from their own knowledge and must only develop a view that complies with all the modelling rules.

If, on the other hand, it is necessary to gather information from others, a brainstorming workshop should be held.

Participants should be sufficient to represent knowledge/concerns of all the involved actors and functional areas of the system.

The brainstorming session should identify sufficient functions and functional exchanges to get from the starting conditions to the ending conditions, and identify the decision and sequence logic that is needed (parallelism, optional branches, iterations).

The number of internal exchanges (that is, functional exchanges between pairs of functions that are both allocated to System of intrest) should be kept to a minimum.

Where new functions or functional exchanges are identified, these should be first created on the corresponding AMOD-056 System functions and exchanges (single system capability).

Where behaviour is expected of an actor in order to reach the end conditions of a system capability, actor functions should be modelled, but these can be captured at a more abstract/placeholder level than the system functions.

Tools and non-human resources

Team for Capella

Optional: basic brainstorming tools

CardinalityOnce per system capability
Completion criteria

The output view complies with its modelling rules.

The content of the output view represents the team's current understanding of the way this system capability is intended to be delivered.

Design reviewARCH.R.3 System capability review
Step done by (Responsible)Lead system architect
Provides input to/assists (Contributes)
  • Expert for GoA4 railway operation
  • System architect
  • Engineer
  • Cross-cutting engineer
Uses outputs (Informed)

RAMS manager

Verification & validation manager