The ABB Group RQDA 040 RK 637 003-AF Relay Module is a Combiflex PLC relay module designed for installation in ASEA Combiflex control racks to provide dedicated relay outputs for external circuits. Identified by the full part number RK637003-AF (a member of the RQDA 040 family), the module reflects ABB/ASEA BROWN BOVERI heritage and is listed by distributors as a Combiflex PLC relay module that has been discontinued by the manufacturer. In typical installations, it would be mounted in a Combiflex rack and wired to the PLC logic to switch field devices through its relay contacts, serving as the interface between automation control logic and controlled loads in industrial automation.
