A light curtain is an example of what type of sensing restraint?

A light curtain is considered a presence sensing restraint because it is designed to detect the presence of a person or object within a designated area. Typically, it consists of an array of light beams emitted from one side to the other; when an object interrupts these beams, it signals the safety system to take action, such as stopping a machine or preventing access to a hazardous area.

This type of sensing is crucial in environments where safety is paramount, as it helps to maintain a safe distance between operators and machinery, thereby reducing the risk of accidents. By detecting when something enters the area and responding accordingly, light curtains play a significant role in enforcing safety protocols and ensuring that workers are protected from moving parts or other dangers.

In contrast, other options like pressure, proximity, and limit switches serve different purposes. Pressure sensors detect force applied, proximity sensors identify the presence of objects without direct contact, and limit switches act upon reaching a specific position or limit in mechanical systems. While these are all important in safety and automation, they do not operate in the same manner as light curtains do in sensing presence.