Safety light curtains are a possible solution for worker protection where risks cannot be eliminated by machinery design or mechanical guards. When a beam of light is broken, the machine or equipment stops, or other actions occur that prevent worker injury.

Basically, two approaches can be considered:

• Point of Operation: Detection of fingers or hands entering point of contact, hazard area. The protective equipment immediately stops the machine or otherwise renders it harmless.
• Perimeter or Area: Once the entry of a person has been detected, the machine stops. The reset control, enabling the operator to restart the machine, must be located outside the hazard area.

In both cases the Safety Light Curtain stops the machine before the hazard point is contacted by the worker and prevents accidental or automatic restart.

Safety light curtains may not be right for all applications.  Simply cutting electrical power may not provide a safe condition.  Interrupting hydraulic or pneumatic pressure, applying brakes, or interfacing with computer controlled machines may require a complex control system.  Light curtain systems could still be installed, but the complexity and cost may be significant. 

For more information on use and application of safety light curtains visit:  Automationdirect.com, Sti.com, or type “safety light curtains” into your favorite internet search engine.

Posted ByDaniel Clark, CECD, WCP®