Home

Automated Assembly Line PLC Controller

Ladder Logic
IEC 61131-3
OpenPLC
Structured Text
HMI Simulation

A four-station automated assembly line controlled by real PLC ladder logic — Load, Process, Inspect, and Eject — with a fail-safe E-stop, a latching fault system, and a browser-based HMI that runs the same control logic live.

</> View Ladder Logic
Assembly line simulator production view, running with 13 parts completed Live ladder logic panel with energized rungs
Fail-Safe Design Normally-closed E-stop and a latching fault that only clears on a deliberate reset
Live Logic Ladder rungs energize in real time as the line runs, scanned like a real PLC
PLC + Web Demo Real Structured Text control program paired with an interactive browser HMI
Overview
  • Controls a four-station assembly line: Load → Process → Inspect → Eject, sequenced one station at a time
  • A single pacing timer advances the line every 2 seconds; a counter tracks completed parts
  • Start, Stop, E-Stop, and Reset operator controls drive the line through an HMI
Engineering
  • Fault latch built as a classic seal-in circuit — a momentary E-stop trips a fault that holds until reset
  • Run control uses a start/stop seal-in with the fault as an interlock, so any fault drops the whole line
  • Logic written as IEC 61131-3 Structured Text and hand-built as ladder rungs in OpenPLC
  • Browser HMI re-implements the identical scan logic in JavaScript for a live demo with no install
Outcome
  • Fail-safe behavior: loss of the E-stop signal stops the line rather than letting it run on
  • Latching fault prevents the line from silently restarting when an emergency clears
  • Same control logic verified in two forms — a real PLC program and a live web simulation