Stop Category 2
A stopping class in which the machine is stopped in a controlled manner but power remains available to the actuators. The motor is held at standstill and the system stays ready to receive commands. Because power is not removed, it cannot be used as an emergency stop function.
Category 2 is designed for normal stops within the production flow: a driver that maintains torque in the standby position can restart without losing position. Because the driver is active, a single electronic fault can produce unintended motion.
- Since power is not removed, the machine is still ready to move.
- It is never sufficient on its own for maintenance and intervention; energy isolation must also be carried out.
- An emergency stop can only be implemented as category 0 or 1.
The typical mistake you encounter in the field is the operator stopping the crane in the category 2 sense and then stepping under the load. On a radio-controlled set, ceasing to give commands does not make the machine safe, it only stops the motion. Before going under a load, energy isolation and mechanical safety steps are applied. Even if the remote control set's relay contacts are open, the panel supply and the contactor circuit remain energised.
The context in which this term is used: Wireless remote control installation: pairing, relays, safety