The Howdy Glossary

Ladder logic is a graphical programming language predominantly used to program PLCs (Programmable Logic Controllers). The language represents electrical circuits with rungs of logic operations and symbols. Ladder diagrams are usually read left to right and top to bottom, simulating the flow of current through relays or contacts in an electrical circuit. These representations are based on traditional relay-based control systems. Each symbol on the ladder diagram represents an input or output connection to the PLC and instructions for logical operations, such as AND, OR, timers, counters, and mathematical functions. This allows engineers without strong software development backgrounds but with experience in industrial automation to easily comprehend programming sequences. Despite being one of the earliest forms of PLC programming languages introduced by Dick Morley back in 1970-1980s for General Motors Hydramatic Manufacturing Systems Division; it continues to be widely used due its simplicity and familiarity among industrial electricians and technicians familiar with electrical schematics helping them mimic real-world electrical circuits into functional applications within automation systems.