PLC | PLC Meaning | What is a PLC Programming?

A PLC Full form is Programmable Logic Controller. A PLC is an solid-state device that drives a machine automatic using the input and output. PLC systems can control processes/machines precisely and efficiently. The instruction is downloaded in the PLC to run the machine as it is with the help of software. This instruction is called a PLC program. The PLC program is downloaded to the PLC’s CPU with the help of a communication cable or memory card. The machine runs in the same manner as the instruction given in the PLC program. In this PLC program, many interlocks are provided so that the safety of the machine and the human remains. Many of the company’s PLC markets are available. Different company’s PLC software is different. PLC program has many languages.

plc systems

Advantages of PLC

  • Easy change Program
  • Fast and Reliable Process
  • Easy Troubleshooting
  • Less Wiring
  • Low Voltage Operation
  • Safety Improve

List of PLC Hardware | What Is a PLC System

  • Rack/ Chassis
  • CPU
  • Memory Card
  • Power Supply
  • Input Module
  • Output Module
  • Communication Module

Rack/ Chassis/ Backplane

The PLC rack is a modular type base with slots in the different similar gaps. This rack holds the power supply module, CPU Module, communication module, and I/O modules. Due to the module connectors in these slots, every I/O module gets power and every module is communicated with PLC.

There are many size chassis in the market.

  • 4-slot
  • 7-slot
  • 10-slot
  • 13-slot
  • 17-slot


PLC-CPU Central Processor Unit

The full form of CPU is the Central Processor Unit. CPU is a decision-making component that executes a PLC program saved in memory.CPU is a Brain of PLC system. PLC program is downloaded from the computer to CPU with the help of RSLogix software.

Memory Card

Memory is a circuit that stores PLC programs and programming data. The memory card is inserted into the memory card slot of the CPU. Whenever the existing CPU is defective, then the program can be downloaded by inserting the first memory card by connecting the New CPU.

Power Supply

A power supply is a type of module that works to Give power to the entire PLC system. The power supply is mounted on the CPU in the first position. The incoming voltage of the power supply is 120-240 V AC And it converts a voltage into 5 volts DC. It goes into the chassis which gives power to all modules in the chassis.

Input Module

The job of the input model is to monitor all sensors and send all data to the CPU. The feedback cable of all sensors is connected to the input module’s  RTB (Removable Terminal Block) Connectors. The machine is equipped with a different type of sensors like Proximity, Photosensor, Limit switch, Pressure Transducer, RTD (resistance temperature detectors), Encoder, potentiometer, angle sensor, ultrasonic sensor, etc. All these sensors are discrete and analog type.

 Output Module

The output modules connect to the supply cable of the output device via RTB. The function of the output module is to give power to the output device to be executed from the CPU of the PLC. Then the device is activated and works by getting the output power. Output Devices like Contactor, Realy, E to P, I to P, drives, Solenoid Valve, Pulse Valve, DC valve, etc.

Communication Module

The communication module handles the entire PLC system. Its main function is to create a network and to communicate all the modules in the network with the CPU of PLC. There are many types of communication modules like EtherNet/IP Module, ControlNet Module, DeviceNet Module.

List of PLC Software

  • Allen Bradley Software – RSLogix 500, RSLogix 5000, RS Studio
  • Siemens Software – Simatic Manager, TIA (Totally Integrated Automation)
  • ABB Software – ABB Automation Builder
  • Omron Software – CX-Programmer
  • Mitsubishi Software – GX Developer
  • Hitachi Software – Pro-H
  • Delta Software – WPLSoft
  • General Electric Software – Versa Pro

TYPES OF PLC ( As Per Make ) | What is PLC a Company

1.Allen Bradley PLC (AB)

2.Siemens PLC

3.ABB PLC (Asea Brown Boveri)

4.Omron PLC

5.Mitsubishi PLC

6.Hitachi PLC

7.Delta PLC

8.General Electric (GE) PLC

What is PLC  programming languages

  • Ladder Logic Diagram (LD)
  • Structured Text (ST)
  • Function Block Diagram (FBD)
  • Sequential Function Charts (SFC)

List of PLC Communication

  • EtherNet/IP
  • Profibus
  • Profinet
  • ControlNet™
  • DeviceNet™
  • SynchLink™
  • USB Client
  • Data Highway Plus™

All About Allen Bradley PLC

Allen Bradley PLC  (AB)

Alan Bradley has many types of PLC which are of various sizes and of various inputs and outputs. It all works on various memory, speed, and protocols. The main PLC that Alan Bradley uses is described below.

SLC Controller

The full name of SLC is a Small Logic Controller. The SLC500 is a small size modular-based PLC which is the base PLC product of Allen Bradley. There are some limited input/outputs of this PLC which can be discrete, analog, and some special type module use. Which is done for automation of a small Size Machine. RSLogix 500 software is used to create this PLC Ladder Logic Programming and I/O configuration. With this software, you can easily create a project. This software helps in troubleshooting and diagnostics of PLC.

MicroLogix Controller

There are many series of PLC available in MicroLogix. 32 I/O can be used in MicroLogix and add extra  I/O module as per requirement. MicroLogix uses Rs Logix 500 software to create PLC ladder programming. With this software, the PLC program can easily be used for download/upload, I/O configuration, and troubleshooting. The RS- 232 protocol is used to communicate MicroLogix PLC to a personal computer.

In compact logics, the available PLC is as follows.

CompactLogix Controller

Allen Bradley PLC

It uses various types of PLC like MircoLogix, in which various features and facilities are found. CompactLogix is more flexible, more I/O, more Efficient, and Faster than MicroLogix. Ethernet is used for communication in CompactLogix with a maximum speed of 1GB/s.

CompactLogix Support Ladder Diagram (LD), Structured Text (ST), Function Block Diagram (FBD), Sequential Function Chart (SFC) Programming language.

In compact logics, the available PLC is as follows.

5069 CompactLogix 5480 Controllers

5069 CompactLogix 5380 Controllers

1769 CompactLogix 5370 Controllers

1768 CompactLogix Controllers

1769 CompactLogix L3x Controllers

ControlLogix Controller

Allen Bradley ControlLogix Controller

A wide range of I/O can be used in ControlLogix. RSLogix 5000 and Studio 5000 software used for Programming create and monitoring.  Controllogix uses separate remote stations, and these remote stations have communication adapters and I/O modules that help control the Big machine. ControlLogix Support Ladder Diagram (LD), Structured Text (ST), Function Block Diagram (FBD), Sequential Function Chart (SFC) in Programming language.

  • Controllogix 1756- L61
  • Controllogix 1756- L62
  • Controllogix 1756- L63 Series
  • Controllogix 1756- L64
  • Controllogix 1756- L65
  • Controllogix 1756- L71 Series
  • Controllogix 1756- L72 Series
  • Controllogix 1756- L73 Series
  • Controllogix 1756- L74
  • Controllogix 1756- L75
  • Controllogix 1756- L81 Series
  • Controllogix 1756- L82 Series
  • Controllogix 1756- L83 Series
  • Controllogix 1756- L84 Series
  • Controllogix 1756- L85 Series

GuardLogix Controller

  • GuardLogix 1756- L61S
  • GuardLogix 1756- L62S
  • GuardLogix 1756- L31S
  • GuardLogix 1756- LSP
  • GuardLogix 1756- L71S Series
  • GuardLogix 1756- L72S Series
  • GuardLogix 1756- L73S Series
  • GuardLogix 1756- L7SP Series
  • GuardLogix 1756- L81ES Series
  • GuardLogix 1756- L82ES Series
  • GuardLogix 1756- L83ES Series
  • GuardLogix 1756- L84ES Series
  • GuardLogix 1756- L8SP Series

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