About the Course

INTRODUCTION

A programmable logic controller (PLC) is an industrial solid-state computer that monitors inputs and outputs, and makes logic-based decisions for automated processes or machines.

PLCs were introduced in the late 1960s by inventor Richard Morley to offer similar functions as that of relay logic systems. Relay systems create the time delay in a faulty system. Technicians then had to troubleshoot an entire wall of relays to fix the problem.

PLCs are robust and can survive harsh conditions including severe heat, cold, dust, and extreme moisture. Their programming language is easily understood, so they can be programmed without much difficulty. PLCs are modular so they can be plugged into various setups. Relays switching under load can cause undesired arcing between contacts. Arcing generates high temperatures that weld contacts shut and cause degradation of the contacts in the relays, resulting in device failure. Replacing relays with PLCs helps prevent overheating of contacts.

PLCs do have disadvantages. They do not perform well when handling complex data. When dealing with data that requires C++ or Visual Basic, computers are the controllers of choice. PLCs also cannot display data well, so external monitors are often required.

COURSE OVERVIEW VIDEO

COURSE OBJECTIVES

To explain advantages and disadvantages, main parts and their functions, the basic sequence of operation of PLC.

To describe the hardware components: I/O modules, CPU, memory devices, other support devices and the functions of the PLC memory map.

To describe the program scan sequence, the communication of information to the PLC using different languages, internal relay instruction.

To explain the identification of common operating modes found in PLCs, writing and entering the ladder logic programs.

To define the functions of Relays, Contactors, Motor Starters, Switches, Sensors, Output Control Devices, Seal-In Circuits, and Latching Relays.

To explain the conversion of relay schematics into PLC ladder logic programs and writing PLC programs directly from narrative descriptions.

To explain the functions of PLC counter instructions, applying combinations of counters and timers to control systems.

To describe the function of selectable timed interrupt and fault routine files and use of temporary end instruction.

To explain the execution of data transfer instructions, interruption of data transfer and data compare instructions.

To explain the basic operation of the PLC closed-loop control system, various forms of mechanical sequencers and their operations.

To describe the operation of a bit and word shift registers and develop programs that use shift registers.

To discuss the operation of various processes, structures of control systems and the method of communication between different industrial processes.

COURSE OUTCOMES

At the end of the course the student will be able to:

Discuss the history of PLC, its sequence of operation, advantages and disadvantages, main parts and their functions.

Describe the hardware components of PLC: I/O modules, CPU, memory devices, other support devices, operating modes, and PLC programming.

Describe field devices Relays, Contactors, Motor Starters, Switches, Sensors, Output Control Devices, Seal-In Circuits, and Latching Relays commonly used with I/O module.

Convert relay schematics and narrative descriptions into PLC ladder logic programs

Analyze PLC timer and counter ladder logic programs

Describe the operation of different program control instructions

Discuss the execution of data transfer instructions, data compare instructions and the basic operation of the PLC closed-loop control system.

Describe the operation of mechanical sequencers, bit and word shift registers, processes, and structure of control systems and communication between the processes.

PREREQUISITES

Need Basic knowledge of Logic gates, Basics of Electronics, Basics of Instrumentation, Basics of Control System is required to understand the concept of PLC

To write a program, you should have a clear idea of the following:

The process of manufacturing the end product. This helps us to go into conditions to build the logic.

The available number of inputs and outputs and identify the purpose of input and output used.

The user should identify the type of PLC that the client wants to use on his factory.

Identify whether the client wants to deploy SCADA to control the outputs and does the client have any plan to increase the scope in the future.

QUESTION PAPER PATTERN

The question paper will have ten questions.

Each full question is for 16 marks.

There will be 2full questions (with a maximum of four sub-questions in one full question) from each module.

Each full question with sub-questions will cover the contents under a module.

Students will have to answer 5 full questions, selecting one full question from each module.