Forcibly Guided Relays

Safety relays are electromechanical switching devices that are designed to implement safety functions and reduce risk. When an error occurs or a detection zone is violated, the safety relay will initiate a safe and reliable response. A traditional relay uses an electromagnet with an electrical coil wrapped around a core of ferromagnetic material. Safety relays are similarly constructed, however, they also use forcibly guided contacts and electronic components with fault-proof semiconductor outputs. They must be designed in such a way that neither an internal equipment fault nor an external fault caused by the actuator or sensor will compromise safety.

Traditional relays use mechanical movement of metal contacts to switch a load on or off. The metal contacts have the potential to weld shut after repeated operation cycles, causing the machine to continue running even after an operator activates an emergency stop process. For this reason, safety relays are required for hazardous machinery. 

Forcibly guided relays are electromechanical switching devices that are designed in such a way that it is not possible for all contacts to be closed at the same time. If a normally open contact fails when trying to open, the associated normally closed contact cannot close when the power supply is switched off. Forcibly guided relays are used in safety circuits in combination with emergency stop switches, interlock switches and light curtains to control outputs. They can also be used to expand outputs for safety controllers and safety relay modules.