AB Allen-Bradley 1756-DHRIOK ControlLogix DH+/RIO Communication Module

Product Summary

The Allen-Bradley 1756-DHRIOK is a ControlLogix DH+/RIO Communication Module Kit by Rockwell Automation. It provides 2 configurable channels supporting both Data Highway Plus (DH+) messaging and Remote I/O (RIO) scanner functionality. The -K suffix denotes a kit configuration that includes the module and terminal blocks for quick installation. It enables communication between ControlLogix controllers and legacy DH+ networks, PLC-5 processors, SLC 500 systems, and remote I/O adapters.

Core Specifications

• Model Number: 1756-DHRIOK
• Type: DH+/RIO Bridge/Scanner Communication Module Kit
• Channels: 2 (independently configurable for DH+ or RIO)
• Communication Protocols: Data Highway Plus (DH+), Remote I/O (RIO), CIP Messaging
• Baud Rates: 57.6 kbps, 115.2 kbps, 230.4 kbps
• Connections: Up to 32 Logix connections; 32 RIO rack numbers per channel
• Backplane Current: 850 mA at 5.1V; 1.7 mA at 24V
• Power Dissipation: 4.4 W typical
• Weight: 0.38 kg
• Manufacturer: Allen-Bradley by Rockwell Automation

Electrical & Functional Characteristics

• Channel Configuration: Each channel independently set via rotary switches for DH+ or RIO mode
• DH+ Node Address: 00–77 octal, set via front-panel switches
• RIO Scanner: Scans up to 32 rack numbers per channel in round-robin fashion
• Message Routing: Supports bridging between DH+ and other networks (ControlNet, EtherNet/IP)
• Block Transfer: Supports block-transfer read/write with remote I/O adapters
• Status Indicators: Module status, channel A/B activity, and diagnostic LEDs
• Cable: Belden 9463 twinaxial (standard); Belden 89463 (XT version)

System Integration & Compatibility

• Primary Platform: ControlLogix 1756 chassis
• Compatible Devices: PLC-5, SLC 500, 1794-ASB, 1771-ASB, 1747-ASB, PanelView terminals, 1336 drives
• Software: RSLogix 5000 / Studio 5000 Logix Designer
• Configuration: Rotary switches for network type and node address; software configuration for RIO adapter lists
• Hot Swap: Supports removal and insertion under power (RIUP)
• Keying: Electronic keying prevents incorrect module insertion
• Related Parts: 1756-DHRIO (module only), 1756-DHRIOXT (Xtreme temperature), 1756-RIO (RIO only module)

Environmental & Operational Limits

• Operating Temperature: 0°C to 60°C (32°F to 140°F)
• Storage Temperature: -40°C to +85°C (-40°F to 185°F)
• Humidity: 5% to 95% RH, non-condensing
• Vibration: 2 m/s², 10 to 500 Hz
• Shock: 30G operating; 50G non-operating
• Approvals: CE, CSA, KC (KCC), RCM, ATEX (Zone 2 with certified enclosure), Marine

Industrial Applications

Widely deployed in manufacturing modernization projects, legacy PLC-5 migrations, distributed I/O systems, SCADA networks, and process control applications requiring integration between ControlLogix platforms and existing DH+ or Remote I/O infrastructure.

Frequently Asked Questions

What is the 1756-DHRIOK used for?

It is a communication module kit that bridges ControlLogix controllers to legacy Data Highway Plus (DH+) networks and Remote I/O (RIO) devices, enabling migration and coexistence with older Allen-Bradley systems.

What does the -K suffix mean?

The -K indicates a kit configuration that includes the module and terminal blocks. The 1756-DHRIO is the module only.

Can both channels run different protocols simultaneously?

Yes — each channel is independently configurable. For example, Channel A can run DH+ while Channel B runs RIO scanner mode.

What cable do I need for the DH+/RIO network?

Use Belden 9463 twinaxial cable for standard installations. For Xtreme temperature applications, use Belden 89463.

What are the related part numbers?

• 1756-DHRIO — DH+/RIO module only
• 1756-DHRIOK — DH+/RIO module kit with terminal blocks (this part)
• 1756-DHRIOXT — Xtreme temperature version (-20°C to +70°C)
• 1756-RIO — Remote I/O only communication module