Block diagram
A block diagram (also block diagram or block diagram ) is a mostly 2-dimensional, graphic diagram of a mechanical-electrical system or a calculation scheme, with the help of which the function of the system can be described. Block diagrams are typically used to provide a higher level of abstraction and thus a better understanding of the function or the interrelationships of the system.
The term block diagram comes from the mostly rectangular elements in such a diagram. However, the shape of these functional basic elements can be freely selected and other geometric figures such as circles, ovals, triangles or rhombuses are often used.
use
Block diagrams are often used to describe hardware or software systems, as well as to illustrate procedures and processes. Such representations are common in hardware and software development and appear under a wide variety of names in the literature. Examples include a. almost all UML diagrams.
In addition, block diagrams are often used as a possible form of modeling a domain-specific language . In these cases there is usually an automatic transformation of the graphic description into a form of code (e.g. C code).
Block diagrams are another widely used form of block diagram . This special form of a block diagram is used in electrics / electronics to show electrical / electronic systems and interconnections in a simplified manner.
elements
In general, a block is always the graphic representation of a specific element from the underlying system or the defined domain with a firmly defined syntactic and / or semantic meaning. In addition, there are also graphic auxiliary blocks (e.g. frames or grouping elements) and textual comments, which are mostly used for structuring, but have no semantic or syntactic meaning in the system or the domain language.
In software development, a block describes e.g. B. a data element, an operator or a control flow element. In most cases, complex functions (e.g. classes in the sense of software development) can also be represented by a simple block. In hardware development , blocks usually represent simple electronic elements such as AND / OR gates or complex functions such as B. the arithmetic-logic unit (ALU) of a processor, in electronics blocks mostly describe circuit elements such as light bulbs, switches or fuses.
Data streams, control flow or other contextual relationships are modeled in the block diagram by connecting blocks with the help of lines. The connections can have different forms. Freehand drawings, arcs, oblique lines or exclusively horizontal and / or vertical lines (also known as Manhattan routing ) are used here. The connections are mostly directed, i.e. have a semantic beginning and a semantic end.
Function block
Function blocks as part of a (function) block diagram are used for the graphic representation of technical procedures, processes and relationships. Function blocks contain textual designations or brief explanations and can contain small graphics or further nested function blocks. The individual blocks are connected by directional arrows on one or both sides, which represent the interfaces and flow direction of the information exchanged between the blocks. The two essential features of a function block are therefore its own technical function (block content) and the function of the interfaces to the neighboring function blocks. Function block diagrams enable the presentation of complex technical processes as a simple overview. The individual function blocks can be expanded in a further block diagram or broken down into further sub-functions ( top-down approach).
use cases
Block diagrams are mostly used when the visualization of data and / or control flow or time / content-related processes are important. Complex control algorithms are often represented graphically or the data flow or communication between individual parts (components) of a large system is mapped. In these, as in numerous other cases, the graphic representation is usually easier for people to understand and comprehend than a textual representation.
An important aspect of block diagrams is the often completely automatic transformation of the graphic specification into another specification form (e.g. C code, Java code or other diagram forms) or the automatic generation of chip layouts from graphic descriptions.
literature
- Nilsson, James W. (1986), Electric Circuits (Second ed.), Addison-Wesley Publishing Company, ISBN 0201126958
- Hayes, John P. (1988), Computer Architecture and Organization (Second ed.), McGraw Hill Publishing Company, ISBN 0070273669
- Bluma, Lars (2002), The Block Diagram and the Systems Engineers. A practice of visualization between science and the public in the US post-war period, in: NTM, 10, 2002, 4, pp. 247–260