What differentiates a safety-rated monitored stop from a hard stop?

• A. A hard stop physically blocks motion and is not restart-safe.
• B. A safety function to stop the robot within defined safety requirements; a hard stop physically blocks motion and is not a safe restart-limiter.
• C. Hard stops provide restart safety, while monitors do not.
• D. Monitored stops are manual and require operator confirmation.

Answer: (B)

The central idea is that a safety-rated monitored stop is a safety function, not just a halt. It stops the robot in a way that meets defined safety requirements and is continuously monitored, with a controlled restart only after safety conditions are revalidated. That means the system will not allow motion to resume until interlocks, guards, and other safety criteria are confirmed—preventing unexpected or unsafe re-energizing.

A hard stop, by contrast, is simply a physical barrier (like a mechanical stop or brake) that stops motion. It does not carry safety-rated monitoring or a guaranteed, verified restart procedure, so it isn’t considered restart-safe.

So the best description is that the monitored stop provides a safety-controlled stop within defined safety requirements and a restart that is validated by safety criteria, whereas a hard stop is merely a physical stop without restart safety provisions.