SAFETY RELAY – VITAL RELAY RS4: Automatic landing door control systems

RS4 safety critical relays (also qualified as vital) are used to drive the “Closed and Locked” safety signal in interface with each Door Control Unit (DCU) of the platform gate. This electric circuitry makes a safety ‘AND’ between each platform screen door and consolidate the “Closed and locked status” at platform level. This status is linked with a signal seen bay the driver who lets train depart from the station once all platform doors are physically closed and locked.