Light curtains are photoelectric sensing devices used to protect personnel and equipment in industrial automation systems. They consist of transmitters and receivers that project and detect light beams to create a protective field. When an object interrupts the beam, the system triggers a safety response (e.g., stopping machinery). These devices are critical in modern manufacturing for compliance with safety standards (e.g., ISO 13849-1) and reducing workplace injuries.
| Type | Functional Characteristics | Application Examples |
|---|---|---|
| Opposed Mode | Separate transmitter and receiver units | Large machinery (e.g., stamping presses) |
| Reflective Mode | Single unit with reflector; cost-effective | Conveyor systems |
| Multi-beam | Multiple parallel beams for high-resolution detection | Robot workcells |
| Single-beam | Simple on/off detection | Entryway guarding |
Typical components include:
| Parameter | Description | Importance |
|---|---|---|
| Detection Distance | 0.3-30 meters | Determines application range |
| Resolution | 10-50 mm | Object size detection capability |
| Response Time | 2-20 ms | Speed of safety reaction |
| Protection Class | IP65-IP69K | Environmental durability |
| Safety Category | Cat. 2/PLc to Cat. 4/PLd | Compliance with safety standards |
Key industries and equipment:
| Manufacturer | Representative Product | Key Features |
|---|---|---|
| SICK AG | OT/OS32C series | Up to 30m detection range, IP69K |
| Banner Engineering | QS30/TL70 | High-temperature resistance, wireless options |
| Omron | F3SG-RA series | Multi-beam with self-diagnosis |
| Keyence | CV-L3 series | High-speed detection for robotics |
Key considerations:
Emerging trends include:
In automotive assembly, SICK's OT series light curtains were implemented at a German plant to protect robotic welding cells. The system reduced unplanned downtime by 40% while maintaining SIL-3 safety compliance.