The Allen-Bradley 1756-DHRIOXT is an extreme-environment product in the ControlLogix Data Highway Plus/Remote I/O Communication Modules. It supports Data Highway Plus –DH+ messaging, Control and Information Protocol –CIP Messaging, and remote I/O communication. The 1756-DHRIOXT helps communication between devices on separate networks and it can route messages through as many as three chassis and four communication networks.

The 1756-DHRIOXT supports 32 logical rack connections on each remote I/O channel and 16 block-transfer connections on each remote I/O channel. Its DH+ connections allow up to 32 DH+ messages per DH+ channel. Its communication rates are 57.6 Kbps for DH+; and 57.6 Kbps, 115.2 Kbps, and 230.4 Kbps for RIO. It has a current draw of 850 mA at 5.1V DC and 1.7 mA at 24V DC. It also supports a maximum of 32 Logix connections.

Chassis-based, the 1756-DHRIOXT can be inserted in any slot in the backplane. It is compatible with the 1756-A4LXT, 1756-A5XT, 1756-A7XT, 1756-A7LXT ControlLogix Chassis, and the standard 1756-PBXT power supply. It features two ports that are individually selectable for DH+ or remote I/O. It has a 30V (continuous) isolation voltage with basic insulation type. A ControlLogix-XT model, it has an operating temperature range of -25-70 °C (-13-158 °F).