1756IB16DOverview of Allen Bradley 1756 IB16D ControlLogix Digital Input Module The Allen Bradley 1756 IB16D is a 16 point DC digital input module for use with ControlLogix systems. It supports 10 30 V DC input signals, offers advanced diagnostics at the point level, and includes time stamped fault reporting. The open style module is designed to mount in a ControlLogix chassis and provides status indicators for inputs, faults, and communication health. Key