Product Overview

The Allen-Bradley 1756-DHRIO is a high-performance ControlLogix gateway module designed to facilitate seamless communication between modern Logix-based architectures and legacy industrial networks. It serves as a dual-channel interface that supports both Data Highway Plus (DH+) messaging and Universal Remote I/O (RIO) scanning. This module is essential for facility upgrades, allowing ControlLogix processors to control existing I/O racks or exchange data with PLC-5 and SLC 500 controllers without replacing established cabling infrastructure.

By integrating the 1756-DHRIO into a standard ControlLogix chassis, users can manage complex migration strategies. The module functions as a bridge, routing messages between networks and providing a high-speed link for time-critical control data. Each of its two channels can be independently configured for either protocol, offering maximum flexibility for hybrid system topologies.

Technical Characteristics and Performance

The 1756-DHRIO is engineered for precise data throughput and low backplane power consumption, ensuring it does not overtax the system power supply while maintaining high network reliability.

• Network Channels: Two independent 3-pin isolated ports.

• Supported Protocols: Data Highway Plus (DH+) and Universal Remote I/O (RIO).

• Communication Rates: Selectable speeds of 57.6 Kbps, 115.2 Kbps, and 230.4 Kbps.

• Maximum Distance: Up to 3,048 meters (10,000 feet) at 57.6 Kbps using Belden 9463 twinaxial cable.

• Backplane Current: 1.7 mA at 5.1V DC; 850 mA at 24V DC.

• Thermal Dissipation: 15.4 BTU/hr with a maximum power dissipation of 4.5 Watts.

• Chassis Slot Width: Occupies a single slot in any 1756 ControlLogix chassis.

• Operational Environment: Standard industrial rating of 0°C to 60°C (32°F to 140°F).

Industrial Applications and Network Integration

This module is the industry standard for phased control system modernization and distributed network management.

• Legacy Controller Integration: Enabling ControlLogix CPUs to read/write data to SLC 500 or PLC-5 systems via DH+.

• Phased Modernization: Replacing an old processor with a ControlLogix rack while keeping existing 1771 or 1746 Remote I/O chassis in place.

• Long-Distance Messaging: Utilizing the robust twinaxial cable physical layer for communication across large-scale manufacturing plants.

• HMI Connectivity: Linking legacy PanelView terminals or SCADA systems to modern Logix controllers through established DH+ drops.