Functional Block Diagram (FBD) is another PLC programming language included in the IEC61131-3 specification. FBD is a graphical programming language that allows users to create function blocks (collections of logic elements that perform a specific function) and connect them together to form a control sequence. FBD programming is based on the concept of ladder logic,

Ladder Diagram programming is a graphical programming language that is widely used in industrial automation. It is part of the International Electrotechnical Commission (IEC) 61131-3 standard, which defines a set of programming languages for programmable logic controllers (PLCs). Ladder Diagram programming is based on the idea of representing the control logic of a system in