Allen-Bradley 1771-IBD SLC 500 Discrete Input Module

Allen-Bradley 1771-IBD is a 16-point DC digital input module for PLC-5 backplane systems. It accepts 10–30 V DC signals and provides 16 discrete inputs in a single module, enabling direct connection of digital sensors such as pushbuttons, limit switches, and other DC-signal sources. Designed for use with 1771 I/O backplanes, this module is part of Rockwell's 1771 I/O family and communicates with the controller via the PLC-5 backplane, following standard input timing and scanning behavior. The 1771-IBD is a discontinued product; Rockwell Automation lists the lifecycle status as Discontinued with a discontinuation date of March 10, 2020. This 16-channel module offers a compact expansion option for digital IO in legacy automation installations that operate on DC signals within the 10–30 V range and rely on PLC-5 control logic. Typical applications include reading digital sensors, stop/start buttons, and other on/off devices in manufacturing lines, packaging operations, and process control where a PLC-5-style I/O architecture is used.