The principle of applying safety light curtains in area protection.

When safety light curtains are applied for area protection, the principle is mainly based on infrared through-beam sensing. By establishing an invisible infrared light grid wall, the system continuously monitors whether any object enters a hazardous area, thereby achieving non-contact safety protection. The following is a detailed explanation of the working principle:

I. Basic Working Principle

A safety light curtain consists of two main components: an emitter and a receiver. The emitter continuously emits multiple beams of infrared light, while the receiver synchronously detects these beams. The emitter and receiver are installed in parallel, forming an infrared scanning zone between them.

Under normal conditions, when all beams are unobstructed, the light curtain maintains the output of a “safe signal,” and the equipment operates normally.

When a person or object enters the protected area and blocks one or more beams, the light curtain immediately detects the obstruction signal and, within an extremely short response time (typically 10 to 30 milliseconds), sends a “stop signal” or “hazard signal” to the control system, triggering the equipment to stop, cut power, or enter a safe state.

II. Features of Area Protection

Full-area detection
The light curtain can be arranged vertically or horizontally. Based on the layout of the emitter and receiver, it forms a continuous detection plane, covering a 2D area to fully detect personnel entry.

Non-contact protection
There is no need for physical fences or protective doors. The light curtain can detect the approach or entry of personnel into a hazardous area, avoiding the operational limitations of traditional protective methods.

Customizable protection size
The protective height and installation distance can be selected according to the area size. For example:
– Horizontal installation protects ground-level robot movement areas
– Vertical installation prevents personnel from entering a robotic arm’s operating range

Support for advanced functions
Area protection is often used together with a “muting function.” For example, in automated logistics systems, the light curtain allows pallets or materials to pass through while preventing personnel from entering.

Fast response shutdown
Once a person enters the danger zone, the equipment is immediately shut down to meet high-level safety standards (such as PL e, SIL3).

III. Typical Application Scenarios

Industrial robot work areas
Light curtains are deployed around the robot operating area to prevent personnel from accidentally entering and being injured by high-speed machinery.

Automated logistics lines
Used for horizontal or multi-sided protection of enclosed conveyor lines or stacker crane zones to ensure no personnel enter during operation.

Around CNC machines or die-casting equipment
To detect if operators are approaching areas with high temperature, high pressure, or rotating equipment.

Large access gates and entrances
Installed on both sides of automatic or lifting doors to detect area occupancy and prevent pinching or accidental opening.

IV. Safety Principle Summary

The essence of area protection using safety light curtains is to “build an invisible safety barrier with infrared beams.” Once any object crosses it, it is recognized as a breach of the safety status, thereby automatically triggering a response from the control system to achieve the purpose of preventing trespass, misuse, and injury.