PLC

Hi friends, today I’m going to give info about PLC. 

A PLC is the acronym of Programmable logic controller. The advent of the PLC began in the 1970s and today in the world of automation; the PLC has become a standard for control. Control engineering has evolved over a long period of time. In the past, humans were the main for controlling a system. As the technology developed electricity has been used for control. One such is relay which allows power to be switched ON & OFF without a mechanical switch. The development of low cost computer has brought the most recent revolution called PLC.

Block diagram of PLC

What a plc is?

A PLC is a user friendly microprocessor based circuit that is used to conduct multiple and complex operations. 

• A PLC is essentially microprocessor or microcontroller based. It has multiple inputs and outputs. It functions according to the software.
• PLC monitors crucial process parameters and controls the process operations accordingly. 
• The PLC replaces much complicated wiring by a single circuit. 
• The input to the PLC can also be taken from analog devices or discrete (on off) devices. 
• The PLCs have tremendous computing capacity but at the same time its size is very compact. 
• Ladder Diagram is primarily used to develop software for programmable logic controllers (PLCs) used in industrial control applications.

Now let’s see what are the advantages of the PLC system:

• PLCs are highly flexible. 
• They have compact size and reduced cost. 
• PLCs are accurate, high speed and reliable. 
• PLCs can be reprogrammed easily & quickly. 
• Data storage and logging is easier since PLCs can be easily interfaced to computers. 
• PLCs can handle large number of inputs and outputs. 
• Programming of PLCs is easier. 

Disadvantages: 

•  For small operations or one or two functions, PLCs are not cost effective. 
• PLCs use electronic devices and microprocessors. They fail sometimes in adverse environmental conditions. 
• If operation is never altered, PLCs prove to be costly.

A few examples of ladder diagrams are:

Ladder diagram for Stair case controller

I hope u all enjoyed this…. Keep visiting!!