PLC Programming Thumb Rules

Here I am sharing thumb rules of PLC programming for Boolean algebra. As I discus earlier post that Ladder language is mostly use for PLC and Ladder is totally based on digital means Boolean algebra. In Boolean algebra basically there are four things are very important 

1. Non Complemented variables
2. Complemented variables
3. Plus (+) operator
4. Dot (.) operator

Here I am telling that when you are drawing ladder then how to convert these logics. Mostly Boolean algebra consist on above four things.

1. Non Complemented Variables

When you fined Non Complemented Variables like A or B then mind it, you will use NO (Normally Open) switch in ladder logic. As you see under symbol.

2. Complemented Variable

And when you fined Complemented Variables like A` or B` then mind it, you will use NC (Normally Close) switch in ladder logic. As you see under symbol.

3. Plus (+) Operator (for OR logic)

And when you fined Plus (+) operator between two variables like A + B then mind it, you will use parallel switches according to variable conditions. As example

4. Dot (.) Operator (for AND logic)

And when you fined Dot (.) operator between two variables like A . B then mind it, you will use switches in series path according to variable conditions. As example