Safety distance calculation for light curtains

摘要

Light curtains are opto-electronic devices that are used to safeguard personnel in the vicinity of moving machinery with the potential to cause harm. Light curtains can be used as an alternative to mechanical barriers and other forms of traditional machine guarding. By reducing the need for physical guards and barriers, light curtains can increase the maintainability of the equipment they are guarding. The operability and efficiency of machinery can also be improved by the use of light curtains by, for example, allowing easier access for semi-automatic procedures. Light curtains are supplied as a pair with a transmitter and receiver. The transmitter projects an array of parallel infrared light beams to the receiver which consists of a number of photoelectric cells. When a person or object brakes one or more of the beams a stop signal is sent to the guarded equipment.