What is ladder logic?

Ladder logic are graphical programming language used for programming PLC in industrial applications. Its a rule based programming language.

Eachrung in the ladder program represent a set of rules. It’s a sequential programming concepts rather than priority execution. That may be considered as a drawback of the system. But it is suitable for small scale industries where the fault factor consider as low.

It doesn’t not require high level programming skills to design and develop the ladder programming. Anyone who knows the logical skills on critical circuits can be able to create the logical programming.

The main application of the graphical  l logic program is in industrial applications, manufacturing and process control, etc.

Connections are made with contacts and coils. We here give you the examples of how ladder programs are used.


When we get input from anyone of the switch then logical OR function will be needed. That can be designed with ladder programming like below we described.

     Logical OR gate(Image Source:theautomationstore.com)

Logical AND:

Logical AND(Image src: theautomationstore.com) 

The ladder logics are also used with the integration of Human machine interfaces to give effective automation system.


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