1756-DH485 | Allen-Bradley | ControlLogix DH-485 Communication Bridge Module

Product Overview

The 1756-DH485 functions as a high-speed communication bridge within the Allen-Bradley ControlLogix chassis. It enables seamless data exchange between the powerful ControlLogix platform and legacy DH-485 networks. This 100% Brand New original module facilitates messaging to SLC 500, MicroLogix, and HMI terminals, ensuring your modern controller maintains full visibility over existing plant-floor hardware. Although the manufacturer officially discontinued this series, we provide factory-new units to support your critical infrastructure maintenance and system expansions.

Technical Specifications

The 1756-DH485 delivers robust networking capabilities through the following technical parameters:

Engineering Advantages

• Legacy Network Bridging: This module eliminates the need for complex protocol converters by allowing a ControlLogix CPU to act as a master or peer on a DH-485 link. It directly addresses the challenge of extracting data from older SLC 500 or MicroLogix controllers.

• Dual-Channel Flexibility: Two independent ports allow the module to manage two separate DH-485 networks simultaneously. This architecture doubles your connectivity throughput without consuming additional rack space.

• Simplified Configuration: The 1756-DH485 integrates directly into the Studio 5000 / RSLogix 5000 I/O tree. Engineers map tags and execute MSG (Message) instructions using standard industrial logic, reducing commissioning time.

• Robust 24V DC Hardware: Designed for high-availability environments, the module draws stable power directly from the 1756 backplane. Its rugged housing resists electromagnetic interference (EMI) commonly found in high-voltage motor control centers.

FAQs

• Is this a refurbished or used unit?

  No. We supply this 1756-DH485 as 100% Brand New original stock. Despite its discontinued status by the manufacturer, our units remain in factory-sealed condition to ensure maximum MTBF (Mean Time Between Failure).

• Can this module reside in a remote I/O rack?

  Yes. You can install the 1756-DH485 in a local ControlLogix chassis or a remote chassis linked via EtherNet/IP or ControlNet, providing significant layout flexibility for large-scale facilities.

• Which cables do I need for the DH-485 connection?

  The module typically utilizes the 1761-CBL-AS03 or 1761-CBL-AS09 cables for connection to peripheral devices. Always verify the pinout requirements of your specific HMI or SLC controller before installation.

• Does it support DH+ (Data Highway Plus)?

  No. The 1756-DH485 specifically handles the DH-485 protocol. If your system requires Data Highway Plus connectivity, you must utilize the 1756-DHRIO module instead.