The Allen-Bradley/Rockwell Automation 1794-IB16D module is a FLEX I/O digital input module with diagnostics capabilities. FLEX series input diagnostic modules like this one are specially constructed to help the users diagnose issues with field devices, open or shorted connections to the field devices, and issues with the power supply. The FLEX I/O system is modular, so having modules like the 1794-IB16D module can reduce industrial automation system commissioning time and also the time needed to correct errors. The 1794-IB16D input module can be mounted on a 1794-TB32 or a 1794-TB32S terminal base. Before the users seat the module in the terminal base unit, they must set a keyswitch on the terminal base to Position 4 and push the Flexbus connector all the way to the left to connect with the adjacent terminal base.

The main advantage of the Allen-Bradley 1794-IB16D input module is its ability to detect disconnected wires, open input field device circuits, shorted input wiring, and reversed “+” and “-“ connectors on the DC power supply or the open power supply circuit. For all 16 inputs, the on-stage mode is declared to be at 24 Volts DC, but it is detected anywhere between 10 and 32 Volts DC. The digital signal can be filtered by this FLEX I/O module and the filtering time can be adjusted by the users. The approximate dimensions of the unit are 45.7 millimeters x 94 millimeters x 53.3 millimeters (1.8 inches x 3.7 inches x 2.1 inches) and it weighs 0.09 kilograms. The 1794-IB16D module has 33 indicator lights, 16 red diagnostic status indicators, 16 yellow ON/OFF status indicators, and 1 red module fault indicator.