What is a PLC and how does it work?

Do you know what is a PLC, what it is used for, and what kind of applications can we do with them?
February 10, 2022 by
What is a PLC and how does it work?
Boot & Work Corp. S.L., Fernandez Queralt Martinez

What is a PLC and how does it work?

A PLC or programmable logic controller is a programmable electronic device that is used for industrial automation.

These devices are basically in charge of processing data, as if it was the brain of electronics, in order to process information and be able to carry out specific activities.

In this way, for example, we could connect a sensor. Then, we can program that, if the value of this sensor exceeds X value, we could trigger an alarm connected to the outputs of the PLC, that would be activated at that moment.

PLCs are made up of a central processing unit (CPU), memory, inputs and outputs:

  • The CPU is used to run the control software.

  • The memory is used to store control programs and process data.

  • And the inputs and outputs are used to connect the PLC to external control devices, such as sensors and actuators, and to receive and send process data.

At Industrial Shields, the PLCs have different CPU:

Arduino based PLC - What is a PLC and how does it work

Arduino based Programmable Logic Controller

Raspberry Pi based PLC - What is a PLC and how does it work

Raspberry Pi based Programmable Logic Controller

ESP32 based PLC - What is a PLC and how does it work

ESP32 based Programmable Logic Controller

            There are countless applications that PLCs can serve that they are used in a wide variety of industries. The following applications are the most noteworthy.

            Industrial Applications

            • Automatic Filling System for Bottles or Liquids.

            • Paper industries for the manufacturing of books, newspapers, and other printed materials.

            • Using the sensors as input to the PLC system, control the temperature or humidity.

            • Glass Industries for manufacturing glass and keeping records.

            • System for packaging and labeling food and beverages.

            Power Station

            • The Smart Grid System monitors and detects fault situations using PLC.

            • Water level sensing and data collection employ real-time PLC technology.

            • In an automation power plant for oil and gas, a PLC is required for tasks like oil filtering, flame safety checks, pilot light on or off, and valve switching for fuel switchover.

            • The Auto Assembly Line System is a tool that PLC may utilize in the Power Substation.

            • Some Electrical Equipment (like Circuit Breaker Tripping, Capacitor Switching) can be automatically operated with PLC.


            • Intelligent Traffic Signal Control System.

            • Automated system for handling machines.

            • Well drainage system automation system.

            • Applications of Pressure Controller in Multi-Motor Pumps.

            • Line Detection and Remote Control System for Mining Equipment.


            • System for Controlling Water Tank Level.

            • Parking and car-washing system.

            • Controlling system for flashing lights.

            • System for opening and closing automatic doors.

            • Remote monitoring software for fans and air conditioners.

            Discover more sectors with this top 50 industrial applications 

            If you want to start programming the PLCs, you can start with:


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            What is a PLC and how does it work?
            Boot & Work Corp. S.L., Fernandez Queralt Martinez February 10, 2022
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            Looking for your ideal Programmable Logic Controller?

            Take a look at this product comparison with other industrial controllers Arduino-based. 

            We are comparing inputs, outputs, communications and other features with the ones of the relevant brands.

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