The RS4 safety relay from CLEARSY: its small size, a major advantage!

CLEARSY’s RS4 safety relays are used to drive the SIL4 “Closed and locked” signal interfaced with the metro platform screen door control unit (DCU).

This electrical circuit performs a safety “AND” between each door on the platform edge and consolidates the “Closed and locked” status at platform level. This state is indicated by a signal visible to the driver, allowing the train to leave the station once all platform doors are physically closed and locked.

The advantage of the RS4 is considerable: the high availability of the control system is ensured by redundancy, as the small size of the electronic relay makes this easy to achieve, compared with gravity-based relays.