What is PLC?
PLC or Programmable Logic Controller, also known as Programmable Controller, is an industrial digital computer designed and built to control industrial processes, such as assembly lines, robotic equipment, and any activity that requires high-reliability control. Is. Facilitation of programming and easy process debugging are the features of PLC. In other words, PLC is a software controller that receives information in binary form at the input and processes it according to a program stored in its memory, and the result of the operation from the output part as Sends commands to command receivers and actuators. In other words, PLC is a logic controller for which the control logic can be defined by the program and can be easily changed if necessary.

How PLC works and is used?
PLCs are designed to withstand harsh industrial environments and conditions and are protected from heat, cold, dust and moisture. PLC has a microprocessor that is programmed using computer language. The program is written on a computer and transmitted to the PLC via a cable.
For the first time, PLC was used in the automotive industry, and this device replaced relays and timers. In a PLC system, the output results in response to the input conditions must be generated in a limited time. If there is no proper response within the defined time, unwanted operation will occur in the system.
The range of PLCs produced ranges from small PLCs with about a dozen I / Os that are compact with the processor to rack-mountable modular PLCs, which have thousands of I / Os and are often networked. Connects to other PLCs and to SCADA.
PLCs have many characteristics, but the most widely used are:
Number of digital and analog inputs and outputs
Number of timers
Number of counters
Number of auxiliary relays
Programmable memory size
Speed ​​of execution of commands
 

PLCs usually have industrial communication ports that allow them to communicate with other devices. This speeds up the exchange of information and allows the PLC more precise control. Today, the use of PLC in industries and factories is increasing and industrial electricians should know how to use it. In fact, every system needs control. There are two types of controls in industrial systems.

Hardware (electric steering circuits)
PL systems (which are themselves divided into 2 parts):
DCS control systems
IPC personal computers

PLC components

Each PLC consists of two parts:
hardware
software

PLC hardware
The hardware that makes up the PLC includes CPU MEMORY, INPUT / OUTPUT, power supply, and programming module.

PLC hardware includes the following:
Power supply unit
Central processing unit
Memory: RAM (includes storage of flags, timers, counters and user programs) and permanent memory (EEPROM, EOROM)
Input terminals: Digital inputs and analog inputs
Output terminals: Digital outputs and analog outputs
Processor communication module
Interface module: input image and output image
Power supply module
 

The following figure shows an overview of the structure of a PLC: