Which statement best describes presence sensing as a protective measure?

• A. It uses lockout devices to isolate energy sources.
• B. It is a manual emergency stop only.
• C. Presence sensing uses devices to detect human presence and can stop or slow the robot when someone is detected.
• D. It involves posting safety notices around the work area.

Answer: (C)

Presence sensing is a protective measure that uses sensors to detect human presence in the robot’s workspace and automatically stop or slow the robot to prevent injury. By monitoring the area with devices such as light curtains, floor mats, area scanners, or vision sensors, the system can immediately respond when a person is detected, bringing the robot to a safe state or reducing its speed until the area is clear. This enables safer interaction in shared workspaces, aligning robot motion with human safety.

This differs from using lockout devices to isolate energy sources, which physically disconnects power rather than actively monitoring presence. It also differs from a manual emergency stop, which requires a person to press a button during an incident rather than a continuous safety response. And it’s not about posting notices, which is an administrative control and does not provide automatic protection.