Computer Engineering Drafting and Design Lecture Handouts - Block Diagram and Flowcharting PDF

CPMPUTER ENGINEERING DRAFTING AND DESIGN PART 1 LECTURE HANDOUTS - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - BLOCK DIAGRAMMING / FLOW CHARTING What is a Block Diagram? A block diagram is a specialized, high-level flowchart us...

CPMPUTER ENGINEERING DRAFTING AND DESIGN PART 1 LECTURE HANDOUTS - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - BLOCK DIAGRAMMING / FLOW CHARTING What is a Block Diagram? A block diagram is a specialized, high-level flowchart used in engineering. It is used to design new systems or to describe and improve existing ones. Its structure provides a high-level overview of major system components, key process participants, and important working relationships. A block diagram example is nothing but a drawing illustration of a system where blocks represent the significant parts. They help to decipher a system's interface, detail, and structural aspects. The detailed study of block diagrams shows the integration of components and blocks' properties. OMG Systems Modelling Language describes the flow and structure of a block diagram. The block components are of five types: o Block o Part o Reference o Standard port o Flow port Types and Uses of Block Diagrams A block diagram provides a quick, high-level view of a system to rapidly identify points of interest or trouble spots. Because of its high-level perspective, it may not offer the level of detail required for more comprehensive planning or implementation. A block diagram will not show every wire and switch in detail, that's the job of a circuit diagram. 1 | Page CPMPUTER ENGINEERING DRAFTING AND DESIGN PART 1 LECTURE HANDOUTS - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - A block diagram is especially focused on the input and output of a system. It cares less about what happens getting from input to output. This principle is referred to as black box in engineering. Either the parts that get us from input to output are not known or they are not important. How to Make a Block Diagram Block diagrams are made similar to flowcharts. You will want to create blocks, often represented by rectangular shapes, that represent important points of interest in the system from input to output. Lines connecting the blocks will show the relationship between these components. Symbols Used in Block Diagrams Block diagrams use very basic geometric shapes: boxes and circles. The principal parts and functions are represented by blocks connected by straight and segmented lines illustrating relationships. When block diagrams are used in electrical engineering, the arrows connecting components represent the direction of signal flow through the system. Whatever any specific block represents should be written on the inside of that block. A block diagram can also be drawn in increasing detail if analysis requires it. Feel free to add as little or as much detail as you want using more specific electrical schematic symbols. 2 | Page CPMPUTER ENGINEERING DRAFTING AND DESIGN PART 1 LECTURE HANDOUTS - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Block Diagram: Best Practices Identify the system. Determine the system to be illustrated. Define components, inputs, and outputs. Create and label the diagram. Add a symbol for each component of the system, connecting them with arrows to indicate flow. Also, label each block so that it is easily identified. Indicate input and output. Label the input that activates a block, and label that output that ends the block. Verify accuracy. Consult with all stakeholders to verify accuracy. 3 | Page CPMPUTER ENGINEERING DRAFTING AND DESIGN PART 1 LECTURE HANDOUTS - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - What is a Flowchart? A flowchart is a graphical representation of steps. It was originated from computer science as a tool for representing algorithms and programming logic but had extended to use in all other kinds of processes. Nowadays, flowcharts play an extremely important role in displaying information and assisting reasoning. They help us visualize complex processes, or make explicit the structure of problems and tasks. A flowchart can also be used to define a process or project to be implemented. A flowchart is a diagram that depicts a process, system or computer algorithm. They are widely used in multiple fields to document, study, plan, improve and communicate often complex processes in clear, easy-to-understand diagrams. Flowcharts, sometimes spelled as flow charts, use rectangles, ovals, diamonds and potentially numerous other shapes to define the type of step, along with connecting arrows to define flow and sequence. They can range from simple, hand-drawn charts to comprehensive computer-drawn diagrams depicting multiple steps and routes. If we consider all the various forms of flowcharts, they are one of the most common diagrams on the planet, used by both technical and non-technical people in numerous fields. Flowcharts are sometimes called by more specialized names such as Process Flowchart, Process Map, Functional Flowchart, Business Process Mapping, Business Process Modeling and Notation (BPMN), or Process Flow Diagram (PFD). They are related to other popular diagrams, such as Data Flow Diagrams (DFDs) and Unified Modeling Language (UML) Activity Diagrams. 4 | Page CPMPUTER ENGINEERING DRAFTING AND DESIGN PART 1 LECTURE HANDOUTS - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Flowchart Symbols Different flowchart shapes have different conventional meanings. The meanings of some of the more common shapes are as follows: Terminal/Terminator Process Decision Document Data, or Input/Output Stored Data Flow Arrow Comment or Annotation 5 | Page CPMPUTER ENGINEERING DRAFTING AND DESIGN PART 1 LECTURE HANDOUTS - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Predefined Process On-Page Connector/Reference Off-Page Connector/Reference Flowcharts for computer programming/algorithms As a visual representation of data flow, flowcharts are useful in writing a program or algorithm and explaining it to others or collaborating with them on it. You can use an algorithm flowchart to spell out the logic behind a program before ever starting to code the automated process. It can help to organize big-picture thinking and provide a guide when it comes time to code. More specifically, flowcharts can: o Demonstrate the way code is organized. o Visualize the execution of code within a program. o Show the structure of a website or application. o Understand how users navigate a website or program. Often, programmers may write pseudocode, a combination of natural language and computer language able to be read by people. This may allow greater detail than the flowchart and serve either as a replacement for the flowchart or as a next step to actual code. Related diagrams used in computer software include: o Unified Modeling Language (UML): This is a general- purpose language used in software engineering for modeling. o Nassi -Shneiderman Diagrams: Used for structured computer programming. Named after Isaac Nassi and Ben Shneiderman, who developed it in 1972 at SUNY-Stony Brook. Also called Structograms. o DRAKON charts: DRAKON is an algorithmic visual programming language used to produce flowcharts. 6 | Page CPMPUTER ENGINEERING DRAFTING AND DESIGN PART 1 LECTURE HANDOUTS - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - How flowcharts are used in numerous other fields Beyond computer programming, flowcharts have many uses in many diverse fields. In any field: Document and analyze a process. Standardize a process for efficiency and quality. Communicate a process for training or understanding by other parts of the organization. Identify bottlenecks, redundancies and unnecessary steps in a process and improve it. 7 | Page CPMPUTER ENGINEERING DRAFTING AND DESIGN PART 1 LECTURE HANDOUTS - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Education: Plan coursework and academic requirements. Create a lesson plan or oral presentation. Organize a group or individual project. Show a legal or civil process, like voter registration. Plan and structure creative writing, like lyrics or poetry. Demonstrate character development for literature and film. Represent the flow of algorithms or logic puzzles. Understand a scientific process, like the Krebs cycle. Chart an anatomical process, such as digestion. Map out symptoms and treatment for diseases/disorders. Communicate hypotheses and theories, like Maslow’s hierarchy of needs. Sales and marketing: Plot out the flow of a survey. Chart a sales process. Plan research strategies. Show registration flows. Disseminate communication policies, like an emergency PR plan. Business: Understand order and procurement processes. Represent an employee’s tasks or daily routine. Understand the paths that users take on a website or in a store. Develop a business plan or product realization plan. Document a process in preparation for an audit, including for regulatory compliance, such as under the Sarbanes-Oxley Act. Document a process in preparation for a sale or consolidation. Manufacturing: Denote the physical or chemical makeup of a product. Illustrate the manufacturing process from beginning to end. Discover and solve inefficiencies in a manufacturing or procurement process. Engineering: Represent process flows or system flows. Design and update chemical and plant processes. Assess the life cycle of a structure. Chart a reverse-engineering flow. Demonstrate the design and prototype phase of a new structure or product. 8 | Page CPMPUTER ENGINEERING DRAFTING AND DESIGN PART 1 LECTURE HANDOUTS - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Types of flowcharts Different authors describe various types of flowcharts in different terms. These people include published experts such as Alan B. Sterneckert, Andrew Veronis, Marilyn Bohl and Mark A. Fryman. Sterneckert, in his 2003 book Critical Incident Management, listed four popular flowchart types, framed around the concept of flow controls rather than the flow itself: o Document Flowcharts: These “have the purpose of showing existing controls over document-flow through the components of a system. … The chart is read from left to right and documents the flow of documents through the various business units.” o Data Flowcharts: These show “the controls governing data flows in a system. … Data flowcharts are used primarily to show the channels that data is transmitted through the system rather than how controls flow.” o System Flowcharts: These “show the flow of data to and through the major components of a system such as data entry, programs, storage media, processors, and communication networks.” o Program Flowcharts: These show “the controls placed internally to a program within a system.” Veronis , in his 1978 book Microprocessors: Design and Applications, outlined three flowchart types based on scope and level of detail: o System Flowchart: Identifies the devices to be used. o General Flowchart: Overview. o Detailed Flowchart: Increased detail. Bohl, in her 1978 book A Guide for Programmers, listed only two: o System Flowchart o Program Flowchart But Fryman, in his 2001 book Quality and Process Improvement, differentiated the types in multiple ways from more of a business perspective than a computer perspective: o Decision Flowchart. o Logic Flowchart. o Systems Flowchart. o Product Flowchart. o Process Flowchart. Additional flowchart types defined by others include: o Swimlane Diagram, a.k.a Swimlane Flowchart: To delineate who does what in cross-team processes. o Workflow Flowchart: To document workflows, often involving tasks, documents and information in offices. 9 | Page CPMPUTER ENGINEERING DRAFTING AND DESIGN PART 1 LECTURE HANDOUTS - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - o Event-Driven Process Chain (EPC) Flowchart: To document or plan a business process. o Specification and Description Language (SDL) Flowchart: To brainstorm computer algorithms using three basic components: system definition, block and process. These related diagrams are also sometimes thought of as types of flowcharts: o Data Flow Diagram (DFD): To map out the flow of information for any system or process. o Process Flow Diagram (PFD), a.k.a. Process Flowchart: To illustrate the relationships between major components at an industrial plant. o Business Process Model and Notation (BPMN 2.0): To model the steps of a planned business process. How to plan and draw a basic flow chart? 1. Define your purpose and scope. What do you hope to accomplish? Are you studying the right things with appropriate start and end points to accomplish that purpose? Be detailed enough in your research but simple enough in your charting to communicate with your intended audience. 2. Identify the tasks in chronological order. This might involve talking to participants, observing a process and/or reviewing any existing documentation. You might write out the steps in note form, or begin a rough chart. 3. Organize them by type and corresponding shape, such as process, decision, data, inputs or outputs. 4. Draw your chart, either sketching by hand or using a program such as Lucidchart. 5. Confirm your flowchart, walking through the steps with people who participate in the process. Observe the process to make sure you haven’t missed anything important to your purpose. 10 | P a g e