Allen-Bradley 1756-DHRI0 Remote IO Interface Module

The Allen-Bradley 1756-DHRI0 Remote I/O Interface Module is a two‑channel DH+ and Remote I/O scanner designed for ControlLogix backplanes, enabling reliable bridge and access between a DH+/RIO network and a ControlLogix controller. The 1756‑DHRI0 is an alternate catalog number in the 1756‑DHRIO family, meaning it provides the same two-channel DH+/RIO interface with the remote I/O scanning features that let a single module manage multiple remote I/O devices across a DH+ or Remote I/O topology. Each channel can be configured for either DH+ or Remote I/O, supporting typical DH+ data rates and routing capabilities to connect remote racks to the controller. Key specifications include up to 32 DH+ messages per channel, up to 32 logical remote I/O connections per remote I/O channel, and up to 16 block-transfer connections per channel, providing scalable I/O traffic and efficient data transfers for mid‑ to large‑scale deployments. The module installs in a 1756 backplane rack and typically uses three terminal blocks for wiring the DH+ and/or RIO connections, offering a compact, two‑channel solution for integrating legacy I/O with modern ControlLogix systems. Ideal applications include connecting multiple DH+ or Remote I/O devices to a single ControlLogix controller, enabling data exchange with legacy equipment, and supporting seamless integration of remote I/O in automation architectures that require bridging disparate networks without a separate gateway device.