Interlocking devices with guard locking, i.e. safety guard locking devices, such as the mechanical safety switch PSENme 1, the safety bolt PSEN b5 and the safety gate system PSENsgate, are fitted to movable guards. Thanks to the safety guard locking device, execution of a hazardous machine function is prevented after the safety gates are opened. Thanks to the safety switch, the safety gate will also stay closed for as long as the operator is at risk from the hazardous movement.
A Category 3 safe interlocking device with guard locking has two safety functions:
- The movable guard will not be released while the motor speed is greater than zero.
- An unexpected start-up is prevented while the movable guard is unlocked or unclosed. (See interlocking device)
Both safety functions have their own safety-related characteristic data and must be evaluated separately.