PLC stands for “Programmable Logic Controller”. 

A PLC is a computer specially designed to operate reliably under harsh industrial environments – such as extreme temperatures, wet, dry, and/or dusty conditions. It is used to automate industrial processes such as a manufacturing plant’s assembly line, an ore processing plant, or a wastewater treatment plant.

The main advantage of PLC over a “hard-wired” control system is that you can go back and change a PLC after you’ve programmed it, at little cost (just the cost of the programmer’s time). In a hard-wired control system, you’re essentially having to rip out wires and start from scratch (which is more expensive and takes longer). Let’s look at an example to better understand this advantage.

Imagine you have a light connected to a switch. In general, the light operates under two conditions – ON and OFF. Now you are given a task that when you turn ON the switch, the light should glow only after 30 seconds. With this hard-wired setup – we’re stuck. The only way to achieve this is to completely rewire our circuit to add a timing relay. That’s a lot of hassle for a minor change.

This is where a PLC comes into the picture, which doesn’t require any additional wiring and hardware to make sure a change. Rather it requires a simply change in code, programming the PLC to only turn on the light 30 seconds after the switch is turned ON. So, by using a PLC, it is easy to incorporate multiple inputs and outputs. This is just a simple example – a PLC has the ability to control much larger and more complex processes. A PLC can be customized depending on the application and needs of the user.