Functional flow block diagram: Difference between revisions

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Revision as of 18:14, 10 April 2018

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[[Image:Functional Flow Block Diagram Format.jpg|thumb|420px|Functional Flow Block Diagram Format.<ref name="SEF01">[http://www.dau.mil/pubscats/Pages/sys_eng_fund.aspx ''Systems Engineering Fundamentals.''] {{webarchive|url=https://web.archive.org/web/20110728000913/http://www.dau.mil/pubscats/Pages/sys_eng_fund.aspx |date=2011-07-28 }} Defense Acquisition University Press, 2001</ref>]]

A '''Functionalfunctional Flowflow Blockblock Diagramdiagram''' ('''FFBD''') is a multi-tier, time-sequenced, step-by-step flow diagram of a [[system]]’s functional flow.<ref>The first version of this article is completely based on the [http://www.faa.gov/about/office_org/headquarters_offices/ato/service_units/operations/sysengsaf/seman/SEM3.1/Section%204.4.pdf NAS SYSTEM ENGINEERING MANUAL SECTION] 4.4 VERSION 3.1 06/06/06.</ref> The term "functional" in this context is different from its use in [[functional programming]] or in mathematics, where pairing "functional" with "flow" would be ambiguous. Here, "functional flow" pertains to the sequencing of operations, with "flow" arrows expressing dependence on the success of prior operations. FFBDs may also express input and output data dependencies between functional blocks, as shown in figures below, but FFBDs primarily focus on sequencing.

The FFBD notation was developed in the 1950s, and is widely used in classical [[systems engineering]]. FFBDs are one of the classic [[business process modeling]] methodologies, along with [[flow chart]]s, [[data flow diagram]]s, [[control flow diagram]]s, [[Gantt chart]]s, [[PERT]] diagrams, and [[IDEF]].<ref name="TD03">Thomas Dufresne & James Martin (2003). [http://mason.gmu.edu/~tdufresn/paper.doc "Process Modeling for E-Business"] {{webarchive |url=https://web.archive.org/web/20061220024049/http://mason.gmu.edu/~tdufresn/paper.doc |date=December 20, 2006 }}. INFS 770 Methods for Information Systems Engineering: Knowledge Management and E-Business. Spring 2003</ref>

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A line with a single arrowhead shall depict functional flow from left to right, see Figure 4.<ref name="FAA06"/>

=== Logic Symbolssymbols ===

The following basic logic symbols shall be used.<ref name="FAA06"/>

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[[Image:7 Inclusive OR Logic.png|thumb|center|360px|Figure 7. “Inclusive OR” Logic]]

=== Contextual and Administrativeadministrative Datadata ===

Each FFBD shall contain the following contextual and administrative data:<ref name="FAA06"/>

* Date the diagram was created