Allen-Bradley 1771-IAD Input Module is a 16-point digital input module that plugs into the 1771 I/O bus to bring status from field devices into a PLC‑5 or SLC‑500 controller. It is an AC/DC (120V) input module that accepts 10–138 V on each input, compatible with 120 V nominal AC or DC sensors and switches. The module provides 16 discrete inputs that map to a 16‑bit data word in the controller’s I/O data table, enabling direct monitoring of each channel. Typical applications include wiring of pushbuttons, limit switches, and proximity sensors for machine control, safety interlocks, and remote I/O in industrial automation.
