The Function Block Diagram (FBD) is a graphical language for

programmable logic controller A programmable logic controller (PLC) or programmable controller is an industrial computer that has been ruggedized and adapted for the control of manufacturing processes, such as assembly lines, machines, robotic devices, or any activity t ...

design, that can describe the function between input variables and output variables. A function is described as a set of elementary blocks. Input and output variables are connected to blocks by connection lines. Inputs and outputs of the blocks are wired together with connection lines or links. Single lines may be used to connect two logical points of the diagram: * An input variable and an input of a block * An output of a block and an input of another block * An output of a block and an output variable The connection is oriented, meaning that the line carries associated data from the left end to the right end. The left and right ends of the connection line must be of the same type. Multiple right connection, also called divergence, can be used to broadcast information from its left end to each of its right ends. All ends of the connection must be of the same type. Function Block Diagram is one of five languages for

logic Logic is the study of correct reasoning. It includes both formal and informal logic. Formal logic is the science of deductively valid inferences or of logical truths. It is a formal science investigating how conclusions follow from prem ...

control Control may refer to: Basic meanings Economics and business * Control (management), an element of management * Control, an element of management accounting * Comptroller (or controller), a senior financial officer in an organization * Controlli ...

configuration Configuration or configurations may refer to: Computing * Computer configuration or system configuration * Configuration file, a software file used to configure the initial settings for a computer program * Configurator, also known as choice bo ...

W. Bolton (2011) ''Programmable Logic Controllers''. p. 14 supported by

standard Standard may refer to: Symbols * Colours, standards and guidons, kinds of military signs * Standard (emblem), a type of a large symbol or emblem used for identification Norms, conventions or requirements * Standard (metrology), an object th ...

IEC 61131-3 IEC 61131-3 is the third part (of 10) of the open international standard IEC 61131 for programmable logic controllers. It was first published in December 1993 by the IEC; the current (third) edition was published in February 2013. Part 3 of ''IEC ...

for a

control system A control system manages, commands, directs, or regulates the behavior of other devices or systems using control loops. It can range from a single home heating controller using a thermostat controlling a domestic boiler to large industrial ...

such as a

(PLC) or a

Distributed Control System A distributed control system (DCS) is a computerised control system for a process or plant usually with many control loops, in which autonomous controllers are distributed throughout the system, but there is no central operator supervisory contro ...

(DCS). The other supported languages are

ladder logic Ladder logic was originally a written method to document the design and construction of relay racks as used in manufacturing and process control. Each device in the relay rack would be represented by a symbol on the ladder diagram with connecti ...

, sequential function chart,

structured text Structured text, abbreviated as ST or STX, is one of the five languages supported by the IEC 61131-3 standard, designed for programmable logic controllers (PLCs). It is a high level language that is block structured and syntactically resembles ...

, and instruction list.

References

{{DEFAULTSORT:Function block diagram Diagrams Industrial computing Programmable logic controllers

See also

References