Product Overview
The Allen-Bradley 1756-DHRIO is a ControlLogix communication module designed to bridge Data Highway Plus (DH+) and Remote I/O (RIO) networks. This module provides two channels (A and B) for connecting legacy devices to modern ControlLogix systems, enabling seamless integration and data exchange across multiple platforms.
Technical Specifications
| Specification |
Value |
| Manufacturer |
Rockwell Automation |
| Brand |
Allen-Bradley |
| Part Number |
1756-DHRIO |
| Series |
ControlLogix |
| Module Type |
Data Highway/Remote I/O Communication Module |
| Location |
1756 ControlLogix Chassis |
| Communication Speed |
57.6 Kbaud, 115.2 Kbaud, 230.4 Kbaud |
| Cable Length |
3048 m (10000 ft), 1524 m (5000 ft), 762 m (2500 ft) |
| Recommended Cable |
Belden 89463 twinaxial, 0.52 mm² (20 AWG) rated at 200 °C (392 °F) |
| Backplane Current (5 Volts) |
1.7 milliamps |
| Backplane Current (24 Volts) |
850 milliamps |
| Power Dissipation (Max) |
4.5 Watts |
| Thermal Dissipation (Max) |
15.4 BTU per hour |
| UPC |
10612598138361 |
| Enclosure |
Open |
| Operating Temperature |
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 |
Key Features & Benefits
- Dual-port design supports both DH+ and RIO protocols, providing flexibility for legacy network integration.
- Supports communication speeds of 57.6, 115.2, and 230.4 Kbaud, adapting to various cable lengths and network requirements.
- Acts as an adapter or scanner on RIO networks, enabling data transfer of analog, digital, block, and specialty data.
- Allows up to 32 Logix connections, facilitating robust multi-device communication.
- Can transfer messages across up to three chassis and four communication networks, extending system reach.
- Works with a wide range of Rockwell Automation controllers, including PLC-5, SLC, CompactLogix, and ControlLogix.
Industry Applications
The 1756-DHRIO is ideal for manufacturing facilities upgrading legacy systems to ControlLogix platforms. It enables communication with legacy PLCs and remote I/O devices, ensuring minimal disruption during modernization. Typical applications include:
- Retrofitting existing DH+ networks to integrate with modern ControlLogix controllers.
- Connecting remote I/O racks in large processing plants to a central control system.
- Bridging communication between older PLC-5 or SLC systems and newer ControlLogix processors.
Installation & Setup
Before installing the 1756-DHRIO module, configure the network type switches for each channel according to your network protocol (DH+ or RIO). Install the module into any slot of a 1756 ControlLogix chassis, ensuring the backplane current requirements are met. The module supports hot insertion/removal, but always follow safety precautions to avoid electrical arcs and electrostatic discharge damage.
For wiring, use the recommended Belden 89463 twinaxial cable. Connect the 3-pin terminal for Channel A and B, and the 8-pin mini-DIN port (parallel to Channel A) as needed. For RIO termination, connect Line 1 to the bottom pin, shield to the middle pin, and Line 2 to the last pin. For DH+ wiring, reverse Line 1 and Line 2 connections.
Compatibility & Integration
The 1756-DHRIO supports communication with Flex I/O, POINT I/O, and messaging functions with PLC-5, SLC, CompactLogix, and ControlLogix controllers. It also supports Control and Information Protocol (CIP) messaging, enabling seamless data exchange across different network types.
Maintenance & Reliability
Regular inspection of cable connections and termination resistors is recommended to ensure network integrity. The module operates within a temperature range of 0-60 °C, making it suitable for most industrial environments. Its open enclosure design requires installation in a protective cabinet to prevent dust and debris accumulation.
Selection Guide & Purchasing Advice
When purchasing the 1756-DHRIO, verify the part number matches your system requirements. Consider the communication speed and cable length needed for your network. Ensure your chassis has sufficient backplane current capacity. For genuine Allen-Bradley parts and reliable service, PLC Source PRO is a trusted supplier.