Ladder Logic Programming

LAD is one of the programming languages defined in the IEC 61131-3 standard.

It is a graphical language inspired by traditional electromechanical relay control circuits.

Key Features of LAD:

• Graphical representation resembling relay logic
• Widely used by electricians and control engineers
• Easy to interpret for maintenance and troubleshooting

Capabilities:

• Supports both basic logic operations and advanced functions
• Useful for real-time control and process automation

Structure:

• LAD program or block is composed of rungs/network
• Each rung/network contains programming instructions representing logical operations