Allen-Bradley 1771-IAD PLC-5 Input Module

The Allen-Bradley 1771-IAD PLC-5 Input Module is a 16-channel digital input card for the PLC-5 family that accepts 120V AC (AC/DC) field signals and translates them into logic states for the 1771 I/O backplane. It is designed to be used in a PLC-5 I/O rack, mounting in the standard 1771 backplane and wiring via a compatible arm such as the 1771-WH for field connections. Each of the 16 discrete inputs is suited for 120V level devices like sensors, switches, and relays, enabling straightforward integration with legacy automation equipment. Electrical characteristics include a nominal input voltage of 120V with an input range typically cited as 79–138 VAC, and a per-module current envelope around 195 mA at 120V, corresponding to roughly 23 W of supply power. The module supports an operating temperature range from 0°C to 60°C, making it suitable for many industrial environments. As part of the PLC-5 ecosystem, the 1771-IAD aligns with standard PLC-5 wiring conventions and addresses within the PLC-5 discrete I/O scheme, offering reliable, rugged performance for retrofits or expansions that require 16 high-voltage digital inputs in a legacy control system.