You need to decide which type of Logic program you are going to use. For many requirements, you can use any of the Logic programs to achieve the required effect. However, in some situations you may need to choose a specific type of program.
By answering the questions below, you can determine whether you need to create a specific type of Logic program or can use the Logic program of your choice:
If you have a choice of which Logic program to use, we recommend that you use the Logic program that you find easiest to use. For many engineers, Ladder Diagrams are the easiest type of Logic program to understand. Ladder Diagrams use relay ladder Logic and are similar to traditional PLC programs.
Like Ladder Diagrams, Function Block Diagrams and Sequential Function Charts are graphical displays. Many users prefer to use graphical programs as they show each of the elements that form the program. It is easier to create a complex program when you can see its elements.
Structured Text (ST) is a text based programming language and is a very flexible type of Logic program. You can use ST programs to provide any type of supported behavior, but to program them you will need a good understanding of the ST language and strong programming skills.
For detailed information on the Logic languages, please refer to the following sections:
When creating Logic programs, you may also need to refer to: