What is Block Diagram – Everything You Need to Know

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What is a Block Diagram?

Are you baffled by the title? If you aren’t, then you must be a user/enthusiast of academic/professional diagrams, like Circuit Diagrams, Schematic Diagrams, Block Diagrams, name them. In case you are wondering what a Block Diagram is, it’s time you put on your reading glasses. As the name implies, a Block Diagram is a drawing illustration of a system whose major parts or components are represented by blocks. These blocks are joined by lines to display the relationship between subsequent blocks.

Now, Block in Block Diagram is the representation of several known properties such that when summed together, they make up the central block diagram. The blocks portray a system as a collection of components responsible for specific tasks in a particular setting.

Block Diagram

Image Source: smartdraw.com


Why are Block Diagrams Important?

What significant role do Block Diagrams play? Well, a Block Diagram is a fundamental way that hardware and software developers utilize to describe these systems while illustrating their workflows and processes. Electricians, on another hand, need them to represent systems and their shifting, for example, the mechatronic systems in the trucking industry.

More often than not, block diagrams are of great assistance when a clear picture of information or control flows is required, besides when a project has a myriad of processes. They make it easier to represent complicated algorithms or flows of details or communication among precise components, for instance, in a mass production facility. Graphically represented project processes are less strenuous to understand than when they are in text form.

When you walk into a room with a block diagram, you will be able to easily decipher the system’s details, interface, and such as structure aspects. It is all thanks to how the blocks are connected intellectually to one another by lines. Blocks are convenient when designing new processes and upgrading those that already exist.


What are the Basic Components of a Block Diagram?

To sufficiently and efficiently represent meaningful processes and display how particular building blocks are interconnected, you need the internal block diagram to study how the blocks’ properties and components get integrated.

In the internal block diagrams, the structure and flows within blocks are described using the OMG Systems Modelling Language (SysML). They provide us with a simplified explanation of how block components are related to one another, what type of data, details, signals, or material flow between the elements and in what direction they flow.

These block components are mainly five and include:

  • Block:  it represents the logical and physical components of the system.

  • Part:  it comprises all aspects modeled using aggregation and association.

  • Reference:  it has all the parts which were developed using aggregation and association.

  • Standard Port:  this is the point of interaction between a system block and the corresponding environment.

  • Flow Port:  this is the point of interaction where a block can emerge from or to.

It is essential to understand the terms used in describing the relationships within Block Diagrams. These are:

  • Association:  it explains the communication amongst the blocks.

  • Aggregation:  this term describes how a unit gets made of parts.

  • Composition:  it is a proper form of aggregation in which the existence of an object which is part of a unit relies on the presence of the group.

  • Generalization:  is a leading relationship between blocks in which a designated block contains all the properties of the entire block diagram.


Uses of Block Diagrams

Being simple and easy to understand, Block Diagrams are used in most industries to illustrate functional processes in respective fields. Next, we will look at three most areas that make use of block diagrams.

4.1. Block Diagrams for Software Design

A block diagram makes a very efficient representation of the overall running of a computer system. It displays the necessary processes needed to get the desired output from a computer from the input you feed into at the start.

In the diagram below, the control unit (CU) and the arithmetic & logic unit (ALU) make up the Central Processing Unit (CPU) in a computer. It is the brain cum the heart of a computer system. Intermediate data and results are contained in the memory unit, awaiting processing. And the disk storage unit houses data and instructions input into a computer system by an input device.

computer system block diagram

Image Source: pdffiles.in


4.2. Block Diagrams for Electrical Engineering

The diagram below is an illustration of an instrumentation channel designed to measure neutron flux, display measured flux, and generate output signals for use by other systems. Every single block marks a stage in the development of a signal used to display on the meter at the lower end. Or to send to systems beyond the boundaries of the diagrams. The blocks are of different sizes and represent either multiple functions, straightforward stage, or one bistable circuit in a more prominent component.

electrical block diagram

Image Source: myodesie.com


4.3. Block Diagrams for Process Control

The third block diagram example is of a feedback control system. It is used to display the essential elements of the system through simple and clear interconnectedness. While studying one, it is very crucial to keep in mind that a block diagram only represents flow paths of control signals. Do not be misled to thinking that it also shows how energy gets transferred throughout the system or process.

feedback control system block diagram

Image Source: akkordeon-frankfurt.de


How to Create a Block Diagram

Having looked at the entailed in a Block Diagram and how useful it can be, we show you how to make one using a fantastic drawing software called EdrawMax Online. It is ‘online’ because it doesn’t require any installation before using it.

You sign in to its web page at https://www.edrawmax.com/online/.and get started.

Drawing a block diagram on EdrawMax online has been made less hectic thanks to 2D and 3D shapes and symbols programmed into the software. The app comes with ready-to-use templates, as well.

To get started, you have to click twice either the Block 2D or Block 3D template thumbnail. This action opens the respective block diagram drawing shapes in the symbol panel. You will love the app’s intuitive and beginner-friendly platform.


So now, let us see how we can use this concept to draw a bar chart with EdrawMax Online:

Step 1:  After registration and verification, log in to the site and choose Basic Diagram under Available Templates. Select either 2D block or 3D block as desired and carry on.

EdrawMax interface

Step 2:  Find the Library pane on the left side of the interface, then tap and hold on a block shape. Carefully drag and drop it onto the canvas displayed on the right side of the screen. To adjust the shape’s size, use the green selection handles.

Step 3:  Now, if you need to write inside the block, double click on it. Add another block shape next to the existing one through drag and drop, as you did in step 2 above.

Step 4:  To choose a connecting design, tap on the Connector icon at the top of the screen to display the drop-down menu. Then tap on the first block shape and draw a line from the edge of this shape to the following form. The connections end turns red indicating, the successful joining of blocks.

Do this until the block diagram gets entirely joined.

connecting blocks


Step 5:  polish up the block diagram by aligning and distributing the shapes and using preferred colors or patterns to identify specific block parts. You have to label the blocks accordingly to ensure you have an ordered and distinct block diagram.
align and distribute blocks


Step 6:  Lastly, choose whether to save or export the finished block diagram.


Tips for Making a Block Diagram

Whether you are a beginner or a pro, we have some tips for you to help you make the perfect block diagram.

  1. Study and understand the system firsthand. Find out the method that you will use to make a block diagram. Figure out its components, inputs, and outputs.
  2. Design and mark the diagram. Use symbols intellectually to represent specific parts of the system. Always connect the blocks using arrows to show the flow of the process. Naming the blocks is very crucial for easy identification.
  3. Show the Input and Output. Ensure you exactly mark the input, which indicates the start, and the output, that indicates the end of a process in a block diagram.
  4. Accuracy verification. Before putting the diagram out there for use, confirm with the concerned and involved team about its accuracy. You should all be on the same page regarding the block diagram’s correctness.


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