The Allen-Bradley 1771-IBN/B is a high-density digital DC input module designed for the Rockwell Automation PLC-5 control system platform. It provides 32 input points, organized into four groups of eight, making it an efficient solution for applications requiring a large number of discrete inputs in a compact space. This module is engineered to interface with a wide range of DC sensors and switches, offering reliable performance in demanding industrial environments. It operates as a high-true (sourcing) input, detecting the presence of a DC voltage signal to indicate an “on” state.