Safety Light Curtain Reference Design

Renesas' quick solutions feature a reference design for a safety light curtain optoelectronic device that is used to safeguard personnel in the vicinity of moving machinery with the potential to cause harm such as hydraulic presses, filter presses, packaging equipment, and winders. The safety light curtain can be used as an alternative to mechanical barriers and other forms of traditional machine guarding. It is a safety device that can urgently stop an operator in an emergency when people or objects are detected at the pinch point. Typically, the safety light curtain is connected to a safety relay which will remove motive power from the hazard in the event when an object is detected.

This safety light curtain consists of a transmitter and a receiver. The safety light curtain controls the infrared emitter (projected side) and receptor (receiving side) from the RL78/G11 MCU via an analog multiplexer. The port outputs a negative-positive-negative (NPN) signal and controls external relay. If the settings are normal and no object is detected in the protected area, an LED will light up to indicate safety. The RL78/G11 MCU is suitable for products with sensor application technology.