This Module Is Designed to Take Approximately 2 Weeks 3 Days a Week for 2 - 3 Hours Each

This Module Is Designed to Take Approximately 2 Weeks 3 Days a Week for 2 - 3 Hours Each

  1. Purpose of Module

This module introduces students to the principles of Programmable Logic Controllers and how they interface to automated processes. By consulting and a designing they will gain an understanding on the importance of PLCs and how Automation and Controls fit into manufacturing.

  1. Time Allocation

This module is designed to take approximately 2 weeks 3 days a week for 2 - 3 hours each.

  1. Classroom Equipment

Computers -- 1 for 2 to 3 students

Office software

Rockwell Software

Spreadsheets (MS Excel)

SLC 500 Simulators

Class room supplies (paper, pencils, ect.)

Smart board/ white board

  1. Student Competencies

Engineering Technology

  1. Principals of Automation Controls
  2. Relationship between machine processes and controls
  3. Physical Characteristics of PLC’s (Input, Output and programming devices)
  4. Familiarity with Programming Software
  5. Identify Standard industrial electrical symbols

Mathematics

  1. Use Binary, Decimals, Hexadecimal, and Octal numbering systems
  2. Algebraic expressions for calculations
  3. Calculate Percentages
  4. Data tables

Communications

  1. Research and Documentation Techniques
  2. Presenting written information and incorporate visuals effectively
  3. Spread sheets in design process
  4. Employ problem-solving skills to solve a team-oriented task.
  5. The use of electronic data sources to obtain information.
  6. Format appropriate documents (proposals, reports)
  7. Demonstrate the five C’s of writing.
  8. Comparing and Contrasting Information
  9. Team Building – Students will collaborate with team members on projects.

Science

  1. Random and Systematic Errors
  2. Measurements
  3. Data Collections - Memory
  1. Module Objectives
  1. Students will understand how automation controls fit into manufacturing environment
  2. Students will understand the relationship between the controller and the machine
  3. Students will define various components and their function.
  4. Students to understand the importance and flexibility of PLC’s
  5. Students will describe the basic principles of Relay Logic & numbering systems
  6. Analyze and make appropriate changes to a PLC automated system.
  7. Students will present written and visual information effectively
  8. Students will research equipment, and present oral reports discussing design recommendations.
  1. Performance Expectations
  1. Students will be evaluated based on their ability to identify major components of Programmable Logic Control System.
  2. Student will be evaluated based on designs, presentations, and ability to perform laboratory experiments.
  3. Students will be graded upon simplicity of program and their ability to problem solve in a team environment.
  4. Numbering systems
  5. Research ability
  1. Introduction

Programmable Logic Controllers

Originally designed to replace relay based control systems in General Motors. Programmable Logic Controllers (PLC) has grown to be a big part of the control industry today. These industries include packaging, pharmaceutical, automotive, and refinery, and, much more. PLCs provide faster production, more reliability, and efficiency. PLCs have constantly increased in capability while decreasing in their cost. These controllers are also known for their performance, reliability, tolerance to vibration dirty air electrical noise and extreme temperatures.

Like any other electronic controls device, PLCs can be programmed to perform a variety of tasks. The more knowledgeable a person is on the PLC’s functions, the easier it is for a person to develop programs and to control complex processes. Functions such as compare, compute, and control instructions are used in almost every PLC. An understanding on how the PLC works makes troubleshooting time shorter and troubleshooting much easier to perform.

PLC’s are broken into five parts, The CPU, Programming device Memory, and I/O. It is common for PLC’s to control more than one process at one time.

Logic Diagrams

Ladder Logic is the main programming language for the SLC 500 PLC. By using ladder logic, the amount of retraining required was greatly reduced. Engineers and trades personnel such as electricians already being familiar with ladder diagrams made the transition from “Ladder Diagrams” to Ladder Logic must simpler.

Input and Output

Inputs and outputs modules for a PLC are used to monitor and control processes. These modules provide an interface that allows the controller to communicate with it's connected devices. Because not all input and output modules are the same it is important to understand their differences to prevent damage or serious injury.

Inputs and Outputs or I/O can be placed into two basic categories: logical or continuous. A switch that turns on a light bulb would be considered logical having only a on and off state. If a dimmer were to be installed the light can then be dimmed to different levels. This would be considered continuous control. Logical control is the most common because of simplicity and accurate control. In this example the switch would be the input device and the light bulb would be the output device. Inputs detect and measure outside variables while outputs control outside devices such as motors, horns, ect.

Think of some devices you would considers input and output devices.

1. Using your design and materials provided, develop and enter into a spreadsheet an I/O list. The list will show all the necessary inputs and outputs used in the program.

  1. Problem Scenario

A small company is expanding their operations by adding a new packaging line. The new packaging line boxes smaller boxes of whiteout into bigger ones. There are six small boxes of whiteout in every big box. There are 8 bottles of whiteout in each small box. They can hire new employees to perform the job, but they feel that installing an automated control system will cut cost, provide reliability, and speed. The packaging line is currently being put into place you have been brought in to help them with the PLC portion of the project.

The company also wants:

  • To be able to count how many bottles of whiteout have gone through the system.
  • How many boxes are packaged pre minute.

The company has provided a drawing that shows the location of devices on the packaging system. They are allowing you to choose the type of PLC and whether or not to use existing or additional devices such as photo-eyes and limit switches. Once the design is complete present your results to the plant representatives.

  1. Using web links provided gather some background information on various input and output sensing devices.
  2. Using the drawing provided add any additional input and/or output devices. Document your recommendations for the necessary devices and describe how they are used in the project. Also decide what type of PLC will be used for the project.
  3. Present your recommendations to your team and collectively design a final project using information from each team member.
  4. Collectively as a team, prepare an oral and visual report describing your recommendations, cost, and how it works in the process.
  5. Draw your system using Ladder Logic format (AutoCAD).
  6. Download programs and make necessary modifications.
  7. Document program accordingly.
  1. Student Workshop Activities

Teaming skills

Problem-based learning

Basic Computer skills (Spreadsheet & windows platform)

Physical Characteristics of PLC (Inputs and Outputs, Programming device, Memory, CPU)

Numbering systems

Comparing and contrasting information

Presenting written information and visuals

  1. Student Activities (Tasks Objectives)
  1. Students will individually research and summarize product data and cost needed for project.
  2. Students will research the different types of PLC used in today’s industry.
  3. Using a given description of the application, students must determine type and placement of equipment that will be suitable for the plant application.
  4. Students will perform calculations using the programmable Logic Controller.
  5. Students will automate a process using basic instruction sets and control knowledge.
  6. Students present their team recommendations through oral and/or written reports.
  7. Participants will develop a drawing of the Logic that the controllers need to perform operations.
  8. Students will present a working program.
  1. Terminology
  1. Central Processing Unit (CPU) – The section of the programmable controller that does the decision making and data storage.
  2. Chassis – A hardware assembly that houses PLC devices such as adapter modules, power supplies, and I/O modules.
  3. Ladder Logic - A program written in a format similar to ladders like diagrams used in electrical drawings.
  4. Instructions – A mnemonic and data address defining an operation to be performed by the controller.
  5. Input Devices – Devices such as a pushbutton or a switch that supplies input signals to the controller.
  6. Output Devices – Devices such as a light or a motor that is controlled by the controllers signal.
  7. Programmable Logic Controller (PLC) – A solid-state control system used to implement specific functions such as report generation, communication, counting, arithmetic, and timing.
  8. Storage Memory – The memory that stores the instruction, input, and output status information.
  9. User Memory – The memory that stores user program or ladder logic.
  10. Data Highway Plus (DH+) - A local area network designed to provide simple communication between PLCs, PC’s, and SLC 500.
  11. Addressing – A device that allows access to a PLC for troubleshooting and programming.
  12. Power Supply – Provides necessary voltage ranges to devices.
  13. Input and Output Modules – Input modules are modules used to convert a input sensor voltage, or current signals into digital data to be sent to the PLC’s processor. While an output module sends an output signal to control an output device. Modules provide the necessary connections between sensors or actuation devices.
  14. Voltage – The amount of electrical pressure in a circuit produced when electrons are freed from atoms.
  15. Processor – the brains of the PLC that organizes data and controls activity.
  1. RESEARCH

Tell what you found in your research about various input and output devices. Describe some of their uses. Do a comparison between the devices, how one compares to another and state their advantages and disadvantages. Decide which types of devices you think are best suitable for the project and explain your reason for your decision. Write a one page paragraph how your teams design is suitable for the project and how the company will benefit from your design.

  1. Evaluation
  1. Instructor Notes

Use the Research Section to lead students to how to perform their oral and written presentation.

2) For student benefit organize student in teams of three.

3) Provide a good learning environment for students. Provide tables, whiteboards, and/or other devices for organizing and recording.

4) Students will need to conduct lab experiments using Bit Level and basic Word Level Instructions.

5) Address basic characteristics of Ladder Diagrams and a PLC System in a visual way using switch and lights as control elements.

6) Introduce students to the different numbering systems such as Hexadecimal, Octal, and Binary. Provide them with a conversion chart.

7) Introduce computer applications such as Rockwell Software.

8) To reinforce teaching use a projector and a white board (smart board).

Research links:

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