The Allen-Bradley/Rockwell Automation CompactBlock I/O 1791D block is a combination of an I/O circuit, a built-in DeviceNet adapter, and a power supply. This block is used when there are space restrictions and where there is the need to have these blocks near sensors and actuators. This series features more than 10 different models that can match any application requirements. Some of these models include 4 sinking input base modules, 8 sourcing inputs, and 8 sinking outputs, and 16 inputs and outputs. The Allen-Bradley/Rockwell Automation CompactBlock I/O 1791D block is compatible with different equipment by using DeviceNet scanners. These are the PLC, SCL or the SoftLogix programmable controllers. 

The CompactBlock I/O 1791D blocks come with a device power range of 10 to 30 Volts DC, a NEMA Type 1 enclosure that is intended for general-purpose protection and it provides a mounting mechanism, short-circuit protection, and it has a compact size that does not require any adapter or power supply. Another important feature of these blocks is their selectable input filters that help the users to choose the best on-to-off delays and the change of state operation that reduces bandwidth usage during operations. The Allen-Bradley/Rockwell Automation CompactBlock I/O 1791D block comes with 3 types of status indicators. These are the logic status indicator, the module status indicator, and the I/O status indicator. Through these indicators, the overall status of the block can be checked easily. The blocks can be mounted side-by-side, on a DIN rail, or directly to a panel. It is recommended to use 14-gauge cables and to install these blocks in a location with temperatures below 60 degrees Celsius.