Glossary · Stopping functions and safe states
Emergency stop category
Also known as: stop category of the emergency stop, E-stop category
German: Not-Halt-Kategorie
In machine safety, the emergency stop category is the stop category according to IEC 60204-1 with which an emergency stop function is carried out. ISO 13850 and IEC 60204-1 require an emergency stop to function either as stop category 0 or stop category 1.
- Machine safety
- EU
In one sentence
The emergency stop category is the stop category, 0 or 1 under IEC 60204-1, in which a machine's emergency stop function is performed.
Example
On a large machining center, the emergency stop is designed as stop category 1: the drives brake the spindle under control and Safe Torque Off is applied once it has stopped.
How it applies
- Engineering: The choice between Stop category 0 and Stop category 1 follows from the risk assessment. Stop category 1 is used where uncontrolled coasting would take too long or create a new hazard, for example with heavy rotating masses.
- Excluded: Stop category 2 keeps power on the actuators after stopping and is not permitted for emergency stop.
- Verification: The stopping behavior, including the stopping time, is measured and compared with the design assumptions.
- Documentation: State the stop category of the emergency stop in the technical documentation and describe the resulting machine behavior in the operating instructions, such as braking time or drives remaining energized during controlled braking.
Emergency stop category vs. ISO 13849-1 Category
The emergency stop category describes how the machine stops. A Category (ISO 13849-1) describes the architecture of the safety-related control parts. An emergency stop in stop category 0 can, for example, be built in Category 3. The two terms are often confused in specifications.