The Omron CS1W-BI102 PLC Backplane Unit provides 10 I/O module slots for extending CS1 Programmable Logic Controller architectures through an Expansion Rack. Its 10-slot configuration creates substantial additional capacity for compatible I/O and specialized modules when the primary rack cannot accommodate all required control functions. The backplane provides the physical installation structure and electrical paths needed for installed modules to operate as part of the extended controller system. This configuration supports larger machine and process-control architectures requiring multiple expansion modules within an organized rack platform. The CS1W-BI102 supports high-capacity rack expansion and belongs to the 10-slot PLC expansion range within Omron factory automation.