Allen-Bradley 1771-ID A Isolated Input Module

The Allen-Bradley 1771-ID A Isolated Input Module is a six-channel, 120V AC/DC discrete input card designed for PLC-5 backplanes, providing isolated inputs to monitor field devices while protecting the controller. Each channel accepts a 120V signal (AC or DC) and preserves galvanic isolation from the backplane to resist noise and transients in industrial environments. Designed to plug into a 1771 I/O chassis, the 1771-ID A integrates with the PLC-5 family and supports common sensing devices such as pushbuttons, limit switches, and proximity sensors. Its isolated input design and compatibility with legacy 120V sensing circuits make it a straightforward choice for retrofits or expansions of existing PLC-5 installations.