The Allen-Bradley 1756-DHRIO is a Data Highway Plus/Remote I/O communication interface module for ControlLogix systems that acts as both a DH+ network adapter and a Remote I/O scanner to exchange messages with DH+ devices and SLC DH+ networks. It can route a message through up to four communication networks and three chassis, enabling flexible DH+ topologies in distributed configurations. The module connects a ControlLogix backplane to DH+ networks and remote I/O, supporting DH+ and Remote I/O communications in DH+ applications. As of December 31, 2024, Rockwell Automation has discontinued the 1756-DHRIO and it is no longer available for sale.
