Reliance 45C904 Shark X Series Input Output Controller

Reliance Electric's Shark X Series 45C904 Input/Output Controller is a brick‑style PLC module that centralizes I/O for Shark-based automation systems. It provides 14 digital inputs and 8 digital outputs, designed to mount in a Shark backplane and to coordinate with other Shark modules to form a compact control rack. The unit operates from 120 VAC and is rated for 2 A, supporting discrete automation tasks such as reading sensor or switch states and driving relays or actuators. As a Shark X Series I/O controller, it serves as the interface between field devices and the main control logic in legacy automation installations. The 45C904 is listed as discontinued by the manufacturer, reflecting its status as older hardware that may still be in service on existing production lines. This model is commonly encountered in vintage Shark architectures, where technicians reference the 45C904 designation to diagnose or document legacy Shark-based control configurations.