An emergency stop (E stop) is typically classified under which safety category?

An emergency stop (E stop) is typically classified under which safety category?

• A. Category 2
• B. Category 1
• C. Category 0
• D. Category 3

Answer: (C)

Safety categories describe how much fault tolerance a safety function has. An emergency stop is a basic safety function meant to immediately halt the machine in an unsafe situation. It is typically implemented with no redundancy and no self-checking diagnostics, relying on a single fault path to stop the system. This simplicity is why it’s classified as Category 0. Higher categories add redundancy and diagnostic coverage, but for a standard E-stop, those features are not part of the ordinary implementation. If an E-stop were designed with dual channels and continuous monitoring, it could fall into a higher category, but the usual, straightforward E-stop is Category 0.

Safety categories describe how much fault tolerance a safety function has. An emergency stop is a basic safety function meant to immediately halt the machine in an unsafe situation. It is typically implemented with no redundancy and no self-checking diagnostics, relying on a single fault path to stop the system. This simplicity is why it’s classified as Category 0. Higher categories add redundancy and diagnostic coverage, but for a standard E-stop, those features are not part of the ordinary implementation. If an E-stop were designed with dual channels and continuous monitoring, it could fall into a higher category, but the usual, straightforward E-stop is Category 0.