Allen-Bradley 1746-A2 Two Slot Expansion Rack

The Allen-Bradley 1746-A2 is a compact two-slot expansion rack for SLC 500 fixed I/O systems, engineered to add two expansion slots to an existing backplane without replacing the main chassis. It functions as an expansion chassis for fixed I/O units in SLC 500 modular or fixed configurations, allowing up to two I/O modules to be mounted in the backplane to extend the system’s I/O capacity. With dimensions of approximately 171 mm high, 80 mm wide, and 145 mm deep (6.73 x 3.15 x 5.71 in) and a nominal weight of about 0.4 kg (1.0 lb), it is designed for back-panel mounting and supports slot fillers to cover unused slots. This expansion rack is typically used in industrial control panels and machine automation environments where two additional I/O slots are needed within an existing SLC 500 installation, enabling scalable, two-slot I/O expansion within the original fixed I/O architecture.