Free resources and Software for learning PLC programming (Ladder Logic )

I would like to introduce you some of the free PLC programming software. With the help of this software you can learn PLC programming by yourself.

One of the free PLC programming software is CLICK. This softwrae is used with CLICK series PLC.You can download the software from following link. Download

Oerating System requiremets : It supports Windows 2000 Windows XP and Windows 7.

It supports Ladder Logic Programming.

Instruction Used for Programming

NO - Normally OPen Contact. Normally OPEN contact is ON when the related bit is on.

Example : when the input bit is high output also will be high.

NC - Normally Closed contact. Normally CLOSED contact is on when the related bit is OFF.



Example : when the input bit is low output will be high.

Compare Contact : This contacts are used for compare operations

Equal to ,Greater than ,Less than





Coil : Output is normally mentioned as COIL

SET : The Set instruction turns ON the associated Bit Memory when the status of the rung is True. The Bit Memory stays on after the rung becomes False. The Set instruction can turn ON more than one Bit Memory at the same time.

Reset :The Reset instruction shall turn off the associated bit memory when the status of the rung is true. The Bit Memory stays OFF after the rung becomes False. A Reset instruction shall turn off more than one bit memory at the same time.

Timers and Counters : Different types of Counters and Timers are used in Ladder logic programming. ON Delay Timer,OFF Delay Timer.UP counter, Down Counter