Omron CPU Base Unit CS1W-BC103, 10 slots, supports up to 10 modules (CPU and power supply not included). Compatible with both C200H and CS series PLC modules. Supports two expansion backplane series, with cable lengths up to 50 meters for long-distance expansion, accommodating up to 72 units and 7 racks. Alternatively, within 12 meters, up to 80 units and 7 racks can be used for large-scale control. An I/O Control Unit and multiple I/O Interface Units can connect two CS1 long-distance expansion series (each up to 50 m, total 72 units and 7 racks). CS1 basic I/O, high-function I/O, and CPU bus units can be installed in any position without special remote programming requirements. Note: C200H units cannot be installed in long-distance expansion racks.