A safety door switch monitors whether a machine guard is closed. Some models only detect the guard position, while guard-locking models can also hold the door closed until hazardous movement has stopped. Selection must follow the machine risk assessment and the required safety-control architecture.
An interlock switch changes its safety contacts when the guard opens. A guard-locking switch adds a mechanism that prevents the guard from opening under defined conditions. Guard locking may be required where a person could reach a hazard before the machine has stopped. The required function should be defined before comparing models.
Electromagnetic and mechanical locking arrangements behave differently during a power loss. Decide whether the application requires power-to-lock or power-to-unlock behavior, and review how personnel can be released during maintenance or an emergency. Do not choose the principle only from normal production convenience.
Check the number and arrangement of positively operated safety contacts and any auxiliary status contacts. The switch must be connected to a compatible safety relay or safety controller according to the machine design. Contact configuration, diagnostic coverage, reset logic and fault detection must be evaluated as a complete circuit.
Tongue actuators, hinges and non-contact designs have different alignment tolerances. Consider door sag, vibration, approach direction and repeated mechanical impact. The actuator should enter smoothly without using the switch body as a door stop.
For guard-locking applications, compare the specified holding force with the expected mechanical load and guard construction. Also measure or calculate the machine stopping time. The guard-release logic must ensure that access is allowed only after the hazardous condition has ended.
Review dust, coolant, oil, washdown, temperature, cable entry and available mounting space. Protect the switch and cable from collision and tampering. Installation spacing and fasteners should follow the model instructions, and maintenance access should not compromise guard integrity.
Provide the guard type, hazard and stopping time, interlock or locking requirement, preferred locking principle, safety-contact arrangement, supply voltage, actuator movement, mounting space, cable requirements and environmental conditions. The final safety function must be validated on the completed machine.
Review mechanical and electromagnetic options in the XURUI safety door switch range. Send the guard layout and circuit requirements through the quotation form for model matching.
