What is the difference between an emergency stop and a protective stop?
An emergency stop is a dedicated function intended for emergency situations. A protective stop is associated with a detected condition or protective device and the configured system response. Their exact behavior, reset conditions, and interaction with surrounding machines depend on the controller and safety design.
What this means in practice
Neither term should be interpreted as a universal instruction to enter a cell. Stopping movement and securing hazardous energy are different activities. Maintenance can require an energy-isolation procedure appropriate to the complete equipment.
Stopping terminology is controller-specific
Manufacturers may distinguish emergency stops, safeguard stops triggered by protective devices, and controller-triggered protective stops. Similar names can describe different functions, power states, and restart requirements. Use the exact terminology and behavior documented for the installed controller.
Record how the tool and neighboring machines respond to each stop, and define the authorized reset procedure. Resetting a stop should not be treated as confirmation that the physical process is ready to continue. Investigate recurring events and use the required energy-isolation procedure for maintenance.
Key points
Identify the documented function of each stopping control.
Train staff on reset and authorized recovery procedures.
Check how the robot, tool, and surrounding machines respond together.
Practical example and next step
Use the equipment manuals and the validated cell documentation to define operating procedures. Repeated stops should prompt investigation of their cause. Avoid bypassing a protective function or repeatedly resetting a fault without establishing why it occurs.