What Is Andon? Meaning, History, and How It Works
Andon is a visual management system that signals a problem on the line the moment it happens, so the right people respond before it becomes lost production.
What Does Andon Mean?
On the factory floor Andon refers to a signal, originally a colored light, that communicates the status of a workstation or line at a glance. Green means running normally, amber means a problem is developing, and red means the line has stopped or needs immediate help. The idea is simple: make problems visible instantly so they can be solved fast.
Where Did Andon Come From?
Andon is part of the Toyota Production System, the lean methodology Toyota developed to build quality in and eliminate waste. It is closely tied to jidoka, or automation with a human touch, which gives any worker the authority to stop the line when they see a defect. The famous andon cord, a pull-cord above the line that any operator can use to call for help or halt production, is the physical embodiment of that principle.
What Is the Andon Cord?
The Andon cord is a cord or button on the production line that lets any worker signal a problem and, if needed, stop the line. Pulling it triggers an Andon signal that brings a supervisor or support team to the workstation immediately. Rather than letting a defect pass down the line, the Andon cord empowers the person closest to the work to raise the issue the instant they see it. Toyota treats a pulled cord not as a failure but as a chance to fix a problem at its source.
How Does an Andon System Work?
A modern Andon system connects equipment, operators, and support teams so status and problems are always visible. When a fault, quality issue, or stoppage occurs, whether triggered by an operator, a machine, or a connected system like SCADA or a PLC, the Andon system changes the displayed status and alerts the people who need to act. Today these systems are largely digital: instead of a single coloured lamp, a digital Andon display shows real-time status, active alarms, and key metrics across every line, and can push the same alert to screens, mobile devices, and two-way radios at once.
From Detection to Resolution
Detect
A problem is detected by an operator, a machine signal, or a connected control system.
Signal
The andon changes state (green to red) and the event is displayed in real time.
Notify
The right responder is alerted on the right device, with escalation if no one acknowledges.
Resolve
The team responds at the source, the issue is logged, and the line returns to normal.
Why Is Andon Still Important Today?
Plant floors are larger, more automated, and more thinly staffed than ever, and a single unaddressed alarm can cascade into hours of downtime. Andon keeps the core promise of lean, surface problems immediately and bring help fast, but extends it across distributed sites and mobile teams. When Andon is connected to a plant’s alarm and notification systems, the same event that lights up a board can also reach an on-call technician’s radio in seconds.
From Andon Concept to Digital Andon System
Andon In Practice
Andon questions, answered
SeQent originated Andon notification for industrial use and continues to power Andon, LED, and digital signage displays across automotive assembly. Operators trigger Andon events from the line, SeQent routes the alert to the right responder on radio or mobile, and the Andon display updates in real time. The full alarm lifecycle is logged for audit and continuous improvement reviews.
Automotive alarm management software monitors SCADA, MES, PLC, and equipment systems across an assembly plant and routes alerts to operators, maintenance, and supervisors on the devices they actually use, including two-way radios, mobile apps, andon displays, and overhead paging. It enforces escalation rules so unacknowledged alarms reach the next responder, protecting assembly line throughput, OEE, and just-in-time delivery commitments.
Alarm notification software for manufacturing monitors SCADA, MES, PLC, and equipment systems for alarm conditions, then routes alerts to the right person on the right device (two-way radios, smartphones, Andon displays, or overhead paging) with automatic escalation if no one acknowledges. It replaces manual dispatch so critical equipment faults, quality deviations, and safety events reach operators in seconds.
See a Digital Andon System in a 15‑Minute Demo
Walk through SeQent’s Andon Visual Display with an expert and see how live production status, active alarms, and escalation work together on a real plant floor.
- Live look at digital andon boards and status displays
- How andon signals connect to SCADA, PLC, and alarm notification
- What rollout looks like across one line or a global plant network
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