Programmable Logic Controller (PLC) Overview

A collection of flashcards to help study the key concepts and functionalities of Programmable Logic Controllers (PLCs).

What does PLC stand for?

PLC stands for Programmable Logic Controller.

What is the primary function of a PLC?

The primary function of a PLC is to control industrial processes.

Who is considered the 'Father' of the Programmable Logic Controller?

Dick Morley is considered the 'Father' of the PLC.

What major advancement in technology enhanced the PLC in the late 1970s?

The introduction of the microprocessor enhanced the PLC.

List one advantage of using PLCs.

PLCs require less wiring compared to traditional relay systems.

What does the CPU in a PLC do?

The CPU acts as the brain of the PLC, controlling logic, monitoring, and communications.

What types of programming languages can be used for PLC programming?

Common programming languages include Ladder Logic, Functional Block Diagram, and Structured Control Language.

What is an Input Module used for in a PLC?

An Input Module provides the electrical connection between field devices and the internal processes of the PLC.

What does a Turn On Delay (TON) timer do in PLC programming?

A TON timer delays the activation of a signal after it has been triggered.

Define a Down Counter in PLCs.

A Down Counter decreases its count for every pulse received until it reaches zero.

In PLCs, what do 'Discrete Inputs' signify?

Discrete Inputs are signals that can be in one of two states: ON or OFF.

What is the purpose of using structured control language in PLCs?

Structured Control Language allows for complex logic representation in a more readable format.

Why is ladder diagram a popular choice for PLC programming?

Ladder diagrams resemble electrical relay control diagrams, making them familiar to electrical engineers.

What is the function of an Output Module in a PLC?

An Output Module converts signals from the PLC processor to control output devices.

Name one application area of PLCs.

PLCs are used in factory automation and machine control.

What is the significance of the Proximity Sensor in a PLC system?

Proximity Sensors detect the presence or absence of objects, providing input to the PLC.

What are the primary components of a typical PLC?

The primary components are the CPU, Input Module, Output Module, and Power Supply.

What does the term 'programming mode' refer to in a PLC CPU?

Programming mode allows the CPU to accept logic downloaded from a connected PC.

Discuss a major feature of Siemens S7-1200 PLC.

The Siemens S7-1200 features an integrated PROFINET interface for communication.

What does the term 'latching' refer to in PLC programming?

Latching allows an output to remain energized until it is reset, regardless of the input conditions.

What is the use of a clock memory in a PLC?

Clock memory allows the PLC to track time-based operations and create pulse signals.