What Is a Safety Light Curtain?

It consists of a transmitter and a receiver that create an invisible grid of infrared light beams. When one or more beams are interrupted, the system sends a stop signal to the machine to prevent injury or damage.

Safety light curtains are widely used as active safeguarding devices in machinery where physical guards are impractical or would reduce operational efficiency.

The transmitter emits parallel infrared beams toward the receiver. Each beam is monitored in real time. When all beams are received correctly, the system remains in a safe state. If any beam is blocked—by a hand, arm, or object—the receiver immediately detects the interruption and triggers a safety output signal to stop or inhibit machine motion.

To ensure functional safety, modern safety light curtains use:

· Redundant internal circuits

· Self-diagnostic monitoring

· Fail-safe (normally closed) output logic

This ensures that any internal fault or wiring failure also leads to a safe machine stop.

· Automated assembly lines

· Presses and stamping machines

· Packaging and palletizing systems

· Robotic cells and welding stations

· Conveyor transfer points

They are especially suitable for applications requiring frequent human access, such as loading, unloading, or manual intervention during machine operation.

· IEC 61496-1 / IEC 61496-2 – Electro-sensitive protective equipment

· ISO 13849-1 – Safety-related parts of control systems

· ISO 12100 – Risk assessment and risk reduction

· EN 61496 – European harmonized standard

Compliance with these standards is essential for CE marking and global market access.

In reality, safety light curtains include redundant safety circuits, self-checking mechanisms, and certified outputs that standard sensors do not provide.

Higher resolution improves detection but may increase nuisance stops and is not always necessary depending on risk assessment.

Light curtains provide linear protection zones, while laser scanners offer configurable 2D areas. Each has distinct advantages depending on layout and access requirements.

A: Most models are designed for indoor industrial environments. Outdoor use requires additional environmental protection and validation.

A: In many applications, yes—but only after proper risk assessment confirms compliance with safety standards.

A: Safety distance is calculated based on response time, machine stopping time, and applicable standards such as ISO 13855.

A: Certified safety light curtains default to a safe state, stopping the machine when faults are detected.

The content is maintained by DADISICK, a manufacturer specializing in industrial sensing and machine safety solutions. Final system design, product selection, and regulatory compliance should be evaluated by qualified safety professionals in accordance with applicable standards and local requirements.