Allen-Bradley 1756-DHRIO Data Highway/Remote I/O Communication Module

Description

The Allen-Bradley 1756-DHRIO is a ControlLogix communication interface module that supports Data Highway Plus (DH+) and Remote I/O (RIO) protocols. It facilitates information exchange among various devices such as PLCs, SLCs, and ControlLogix controllers across different networks.

Key Features:

1. Dual Channels:
   • Two channels with selectable communication speeds of 57.6 Kbps, 115.2 Kbps, or 230.4 Kbps (depending on cable length).
2. Communication Protocols:
   • Remote I/O (RIO): Supports communication with remote I/O devices.
   • Data Highway Plus (DH+): Messaging between compatible devices.
   • CIP Messaging: For Control and Information Protocol communication.
3. Connection Capabilities:
   • Up to 32 Logix connections.
   • Functions as an adapter or scanner for RIO networks, transferring data types such as analog, digital, block, and specialty data without requiring message instructions.
4. Network Configuration:
   • Daisy-chain topology for DH+ and RIO networks.
   • Requires terminating resistors at the first and last nodes, with values depending on network speed:
     • 82 Ohms for 230.4 Kbps.
     • 150 Ohms for 57.6 Kbps and 115.2 Kbps.
   • Uses Belden 89463 twinaxial cable with specific wiring for RIO and DH+ protocols.
5. Hot-Swappable:
   • Modules can be installed or removed with chassis power applied (in nonhazardous environments and with proper precautions).
6. Compatibility:
   • Compatible with Flex IO, POINT IO systems, and messaging functions for PLC 5, SLC, CompactLogix, and ControlLogix controllers.
7. Safety Considerations:
   • Static discharge precautions must be observed to protect the module from electrostatic damage.

---

Technical Specifications

Attribute	Details
Manufacturer	Rockwell Automation
Brand	Allen-Bradley
Catalog Number	1756-DHRIO
Series	ControlLogix
Module Type	Data Highway/Remote I/O Communication Module
Chassis Location	1756 ControlLogix Chassis
Communication Speeds	57.6 Kbps, 115.2 Kbps, 230.4 Kbps
Maximum Cable Length	3048 m (10,000 ft), 1524 m (5,000 ft), 762 m (2,500 ft)
Recommended Cable	Belden 89463 twinaxial, 0.52 mm² (20 AWG), rated at 200 °C (392 °F)
Backplane Current (5V)	1.7 mA
Backplane Current (24V)	850 mA
Power Dissipation (Max)	4.5 Watts
Thermal Dissipation (Max)	15.4 BTU/hour
Enclosure Type	Open
Operating Temperature Range	0–60 °C (32–140 °F)
Slot Width	1
Weight	0.64 pounds (0.293 kilograms)
Spare Connector Kit	Phoenix MVSTBR2.5/3-ST BK AU

---

Revisions

Revision Part Number	Alternate Names
1756-DHRIO Ser A	1756-DHRIO/A, Series A, Rev A
1756-DHRIO Ser B	1756-DHRIO/B, Series B, Rev B
1756-DHRIO Ser C	1756-DHRIO/C, Series C, Rev C
1756-DHRIO Ser D	1756-DHRIO/D, Series D, Rev D
1756-DHRIO Ser E	1756-DHRIO/E, Series E, Rev E

---

Installation and Wiring Guidelines

1. Network Termination:
   • Install terminating resistors based on network speed across Line 1 and Line 2.
   • For RIO:
     • Line 1 connects to the bottom pin (Terminal 1).
     • Shield cable connects to the middle pin.
     • Line 2 connects to the last pin.
   • For DH+:
     • Reverse the connections of Line 1 and Line 2.
2. Power and Chassis Requirements:
   • Install and connect a ControlLogix power supply and chassis before installing the module.
   • Ensure power requirements are met for multiple module installations in the same chassis.
3. Static Discharge Protection:
   • Discharge any static before handling the module to avoid damage.

---

Applications

The 1756-DHRIO is ideal for industrial automation and communication tasks, supporting various network types and enabling reliable data exchange between devices across different systems and protocols.