Ladder Logic is a widely used programming language based on circuit diagrams of relay logic hardware. It can be used to develop software for programmable logic controllers (PLC’s). The programs resemble ladders with two vertical rails on each side with horizontal rungs between them. Each rung of a ladder typically has a coil on the far right. There are different types of coils that represent whether a rung is closed or open. There are also different types of contacts for coils that represent whether a contact may be open or closed depending on the input. Function blocks are often available to help with implementing arithmetic operations or complex functions.
