Allen-Bradley 1756-DHRIO ControlLogix Communication Interface

The Allen-Bradley 1756-DHRIO is a two‑channel DH+ / Remote I/O communication interface for ControlLogix that plugs into a CLX backplane to bridge DH+ networks with a ControlLogix processor. Each of its two ports can be configured as a DH+ gateway or universal Remote I/O, enabling data exchange between DH+ devices and remote I/O racks or PLCs controlled by a CLX system. The module is powered from 24 V DC (C01 24VDC) and occupies a single chassis slot, functioning as a DH+ gateway and remote I/O scanner within the ControlLogix backplane. Rockwell documentation positions the 1756-DHRIO as a Data Highway Plus / Remote I/O communication interface capable of routing messages between DH+ networks and remote I/O devices. Typical use cases include migrating legacy PLC-5/SLC 500 DH+ networks to ControlLogix and serving as a DH+ gateway for remote I/O racks, allowing legacy DH+ devices to be integrated into a modern CLX control system.