Interface Relay - R600 Series ABB R600 series interface relays are used for electrical isolation, amplification and signal matching between a PLC, PC or field bus system and the sensor/actuator level. The compact design and different connection terminal possibilities optimise your panel installation. Features and Benefits Screw or spring type terminals Wide range of output options Built in RC circuit Leakage current protection on the input side Available with visible or covered switch Manual or automatic actuation LED for the indication of the operational state