Safety light curtains

Safety light curtains

Safety light curtains are used where hazardous areas must be secured. They are optoelectronic safety devices consisting of one transmitter and one receiver. They conform to the safety requirements of type 2 / SIL 1 or type 4 / SIL 3.
Typical applications include access prevention or hazardous area monitoring of robot cells and production lines. For food and beverage applications, units with protective tubes and high protection ratings are offered. Safety light curtains with floating blanking can be used to safeguard material feed processes on presses and saws.

What Are Safety Light Curtains?

Safety light curtains are optoelectronic safety devices used to protect personnel near hazardous machinery. They function as invisible light barriers—projecting infrared beams between an emitter and a receiver. If a beam is interrupted by a hand, body, or object, the system sends an immediate stop signal to the machine.

Used as non-contact light guards for machinery, they offer safe access control without obstructing workflows and help manufacturers comply with safety standards like Type 4 / SIL 3 / PL e.

How Do Safety Light Curtains Work?

An emitter sends a series of synchronised infrared beams to a receiver. When all beams are clear, the machine operates normally. If any beam is blocked, the system triggers a stop.

ifm’s safety light curtains feature:

• Slim, rugged housings for tight spaces

• Standard M12 connectors for quick installation

• LED indicators for alignment and diagnostics

• Optional IO-Link connectivity for monitoring and configuration

These systems are ideal for environments requiring low-maintenance light guards for machinery.

Types of Safety Light Curtains

ifm offers models designed for different protection levels:

• Finger protection (14 mm resolution) – For close-range interaction zones

• Hand protection (30 mm resolution) – For access points on machines

• Body protection – For perimeter guarding around larger equipment

Protective field heights range from 160 to 1810 mm, with robust options like the OY407S and OY434S designed for hygienic or washdown environments.

Advantages and Disadvantages

Advantages

• No moving parts = minimal maintenance

• Fast response times (< 20 ms)

• Simple installation with standard connectors

• Floating blanking and muting options for dynamic applications

Disadvantages

• Requires proper alignment and mounting stability

• May need additional protective tubes in harsh or wet environments

• Susceptible to optical interference if not properly shielded

Applications: Where They’re Used

Safety light curtains serve as effective light guards for machinery in:

• Packaging and palletising lines

• Robotic cells

• Presses and stamping machines

• Conveyor systems

• Food and beverage environments (with high IP protection)

How to Choose the Right Model

1. Determine the resolution: Choose based on whether finger, hand, or body protection is required.

2. Measure the access height: Select a protective height that matches the guarded area.

3. Consider the environment: Use models with IP65/IP67 ratings or protective tubes in dusty or washdown settings.

4. Integration needs: Standard PNP outputs or IO-Link for data and diagnostics.

5. Advanced features: If needed, select models with floating blanking, muting, or test inputs.