Steps of functional analysis

 Functional analysis

Functional analysis is a method whose purpose is to research and characterize the functions offered by a product to satisfy the needs of its user.

The external functional analysis

It describes the user’s point of view. It is interested in the product as a «black box» capable of providing services in its environment during its cycle of use.

Horned beast diagram 

The horned beast diagram is a tool that has allowed us to identify the main need or goal

This diagram answers three questions:

Who does he serve?
What is he doing?
For what purpose?

The horned beast diagram of our system is illustrated in the figure below:

Octopus diagram

The role of octopus diagram is to specify the relationships that exist between elements of the system environment. To do this, we will define the service functions, separated into main FP functions, and FC constraint functions.

The octopus diagram of our system is as follows:

The internal functional analysis

The internal analysis of an existing system makes it possible to represent the transition from service functions to technical functions and then to constructive solutions that will be materialized by components and constituents.

SADT Diagram

SADT (structured technique of analysis and modelling) is an analytical tool that allows us to know what a system does or how it acts and where it is found. This diagram is based on four questions:

What is the boundary of the studied system?

Function: It is characterized by an action on materials of works or entries.

What’s the system for?

Incoming work materials: They are the materials of works modified by the function in question. They are of three types: product (matter), energy, information.

What’s the system doing?

Outgoing works of art: These are mainly works of art with their added value.

What does the system do to the work matter?

Control or control constraints: These are the parameters that trigger or modify the realization of a function.

FAST Diagram

The FAST diagram allows us to define all the constructive functions of our control and monitoring system, based on the service functions that the system must perform. On the other hand, it will clarify the technical choices of the system through the establishment of technical functions.