Allen-Bradley 1756-DHRIO DH+ / Remote I/O Communication Interface Module
Dual Communication Channels
Data Highway Plus (DH+)
1756-DHRIO pdf
Place of Origin:
USA
Brand Name:
Allenbradley
Dual Communication Channels
,Data Highway Plus (DH+)
,1756-DHRIO pdf
1756-DHRIO
ControlLogix Data Highway Plus / Remote I/O Communication Module. Designed to connect DH+ networks and remote I/O devices with ControlLogix-based control systems.
Product Overview
The Allen-Bradley 1756-DHRIO is a ControlLogix communication interface for Data Highway Plus (DH+) and Remote I/O networks. It supports communication between ControlLogix controllers and PLC or SLC devices across supported networks. When a channel is configured for Remote I/O, the module operates as a scanner and exchanges discrete and block-transfer data with remote I/O devices.
DH+ Network Communication
Provides DH+ messaging and routing between devices on DH+ networks and other supported networks, including Ethernet and ControlNet paths through the ControlLogix system.
Remote I/O Scanning
Acts as a Remote I/O scanner, exchanging I/O data with remote adapters and allowing the ControlLogix controller to communicate with remote I/O devices.
Technical Specifications
Additional Technical and Configuration Details
System Applications & Fault Scenarios
The 1756-DHRIO is used in ControlLogix systems that need to retain or bridge communication with existing DH+ networks and Remote I/O installations. It is relevant to plants integrating legacy PLC-5 or SLC controllers, remote I/O adapters and ControlLogix-based control equipment.
DH+ Network Interruption
When PLC or SLC devices become unreachable through a DH+ link, maintenance teams may inspect the communication path, node addressing, routing configuration and DHRIO interface.
Scanner or Adapter Offline
If remote I/O data stops updating or an adapter is not detected, the scanner channel, network wiring, adapter status and scan-list configuration may require investigation.
Control Data Unavailable
Communication faults can interrupt controller-to-device data exchange, affecting machine sequences, remote I/O control and production coordination. The resulting downtime depends on the system architecture and affected process.
Installation, Configuration & Diagnostics
Chassis Installation
The module is installed in a ControlLogix chassis. Align the circuit board with the chassis guides and ensure that the backplane connector is properly seated. When replacing an identical module and restoring the same system operation, the manual specifies installation in the same slot.
Network Setup
Set the channel network type and, for DH+ operation, the applicable node address. Configure the routing table and channel settings according to the network design and controller application.
Useful Status Messages for Troubleshooting
Product Lifecycle & Sourcing
Rockwell Automation lists the 1756-DHRIO as discontinued, with a discontinuation date of December 31, 2024. The product page identifies its replacement category as Engineering Replacement. A specific direct replacement should not be assumed from that category alone; confirm the required network functions, channel configuration, controller platform and application requirements before selecting an alternative.
AMIKON supports sourcing requests for the 1756-DHRIO. Please provide the full catalog number and, where possible, the module series and application details so the requested item can be checked against your system requirements.
About AMIKON Industrial Supply
AMIKON Industrial Supply supports industrial automation parts sourcing for maintenance teams, system integrators and equipment operators. Our focus is practical product identification, order coordination and communication throughout the sourcing process.
For discontinued control-system components such as the 1756-DHRIO, sharing the existing part number, equipment details and application requirements helps us understand the sourcing request more accurately.
Delivery, Testing & Warranty
Frequently Asked Questions
It has two channels, Channel A and Channel B. Each channel can be configured for DH+ or Remote I/O operation, subject to the documented channel limitations.
No. The 230.4 Kbps DH+ setting is supported on Channel A only. When Channel A is configured for 230.4 Kbps DH+, Channel B is disabled.
Check the module display and channel status, network cabling, node address, channel mode, routing table and remote adapter configuration. The displayed status message can help narrow down the fault.
Related Models
Other industrial automation parts available for sourcing reference. These model numbers are independently listed items and do not indicate compatibility, interchangeability or approved replacements for the 1756-DHRIO.
View Related Models
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