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Automation Networks

Data Highway Plus Protocol

The Allen-Bradley Data Highway Plus (DH+), developed by Rockwell Automation, is a key communication network for industrial automation. Originating in the 1980s, DH+ improved upon its predecessor, Data Highway, becoming popular in industrial settings.

Early Days:

Rockwell Automation introduced Data Highway in the 1980s, marking a revolution in industrial communication. This system let devices like programmable logic controllers (PLCs) interact efficiently. But as demands grew, so did the need for a more advanced system. Enter Data Highway Plus.

Key Features:

  1. PLCs and Devices: DH+ networks connect PLCs, motor controllers, and human-machine interfaces. These devices use DH+ modules for communication.

  2. Software Tools: Engineers use Rockwell Automation software, like RSLogix 5 or RSLogix 5000, to configure DH+ networks.

  3. Communication Protocol: DH+ uses a special protocol to manage data transmission across the network.

  4. Physical Layer: The network often relies on RS-485 serial interfaces, sometimes using coaxial cables in older setups.

  5. Hardware Components: Essential items like communication cards and connectors form the backbone of a DH+ network.

Operation Simplified:

  1. Configuring Devices: Each device gets a unique node address for identification.

  2. Making Connections: Devices link up using cables and connectors in a linear or multidrop layout.

  3. Setting Parameters: The network software sets communication details like baud rate and parity.

  4. Exchanging Data: Configured devices can now share data and control commands, vital for automated processes.

  5. Polling and Scanning: A master device coordinates communication, ensuring efficient data handling.

  6. Real-Time Control: DH+ excels in scenarios needing timely responses, like manufacturing.


  • Interoperability: DH+ ensures Allen-Bradley devices work seamlessly together.
  • Reliability: Known for its robust performance, DH+ suits mission-critical tasks.
  • Predictable Timing: It offers consistent communication, key for real-time operations.
  • Legacy Integration: Older systems can easily join modern setups, thanks to backward compatibility.
  • Ease of Use: The network’s setup and management are user-friendly.


  • Manufacturing: DH+ orchestrates machinery and production lines.
  • Process Control: It’s crucial in chemical, pharmaceutical, and petrochemical industries.
  • Utilities: DH+ helps in managing power distribution and electrical substations.
  • Building Automation: It plays a role in managing HVAC systems and lighting.
  • Water Treatment: Vital in automating water and wastewater processes.
  • Material Handling: DH+ controls systems like conveyor belts in logistics centers.

Our Products

ANC-100e: Ethernet/IP to DH+ Converter

The ANC-100e DH+ converters provide communications between newer Ethernet Technologies and DH+ legacy PLC-5s and SLC/504s

The ANC-100e is a pocket-sized, high performance, Industrial Rated Ethernet DH+ Converter.  Features include: Ease of Configuration via Web Interface and DH+ Auto Polarity Detection and DH+ Auto Baud Rate Detection.

$1,295 USD List.

Data Highway Plus to Ethernet (S02)

ANC-120e: USB to DH+ RSlinx PLC

The ANC-120e is a competitive alternative to AB’s 1784-U2DHP PLC Programming Cable

Is an economical and high performance USB-to-Allen-Bradley Data Highway Plus converter interfacing major HMI, SCADA, PLC Programming packages to Devices on DH+. Its features significantly outperform AB’s 1784-U2DHP PLC Programming Cable operating at 12 Mg USB speed with the Controllogix Ethernet/IP Driver.
The ANC-120e works with all SCADA, MMI, PLC programming packages installed on your PC with USB direct access to the DH+ network and stations. These packages include RSLINX/LOGIX Classic & Enterprise with RSLOGIX 5/500, Wonderware DAServer & TCP/IO Server, Citect, and Kepware using Controllogix Ethernet/IP Drivers.
$1,295 USD List.

USB To Data Highway Plus (DHP, DH+) – Using the ANC-120e, a lower cost alternative to the 1784-U2DHP


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