What is PLC

 What is PLC

A programmable logic controller or PLC is simply computer that is programmed to control certain process in industries like petroleum, steel or Automative.

Every PLC is composed of three main parts input,cpu and output.

Suppose that we have an electrical motor and a push button, we want the motor to turn ON when the button is pressed. When the button is pressed again, we want the motor turn off. This function is similar to the function of the power button on your TV remote. To do this, we must first write a program for this operation on a computer and these download it to the cpu. Then we connect the switch to the input and the motor to the output.

Now if we press the button an electrical signals will be sent to the plc the plc input will deliver this signal to the CPU but first must present it in a format that the CPU can process why because the CPU is a computer system and cannot process the raw Electrical signal. 

The cpu will process the data received and send the result to the output. The output turns the data to a raw Electrical signal again and applies that to the motor and turns it on. Now if we press the button again,the process repeat and the motor will turn off.