Allen-Bradley 1756-DHRIO Digital High Speed I/O Module

The Allen-Bradley 1756-DHRIO is a ControlLogix DH+/RIO communications bridge and remote I/O scanner module that links a ControlLogix backplane to Data Highway Plus networks and to remote I/O devices. Its dual channels, labeled A and B, can be configured for DH+ networks or as Universal RIO operation, enabling the controller to poll, read, and write I/O data across multiple networks and racks without replacing legacy equipment. Rockwell documentation notes that the 1756-DHRIO can route messages through up to four DH+ networks across three chassis, providing flexible topology options for complex automation systems. As a DH+/RIO bridge, the module serves as the RIO scanner on its configured channel(s), offering seamless integration between ControlLogix and older Remote I/O devices while using Studio 5000 or RSLogix 5000 configuration tools. Designed for use in ControlLogix environments, it supports standard remote I/O addressing, real-time data exchange, and straightforward configuration through Rockwell's engineering software.