Allen-Bradley 1784-U2DHP USB to Data Highway Plus Cable Overview

Product Overview

The 1784-U2DHP is a communication peripheral from Allen-Bradley (Rockwell Automation) that enables any configuration or programming workstation with an USB port to connect to a DH+ network. It supports PLC-5 processors (excluding Classic models like PLC-5/10, PLC-5/12, PLC-5/15, and PLC-5/25) and SLC 5/04 processors. This device replaces the 1784-PCMK adapter card and 1784-PCM6 cable, providing a modern, compact alternative.

Technical Specifications Breakdown

Key parameters for the 1784-U2DHP are listed below for quick reference:

Industry Applications

Legacy System Integration

Manufacturing facilities often operate PLC-5 or SLC 5/04 controllers on DH+ networks. The 1784-U2DHP allows engineers to connect modern laptops for programming, monitoring, and diagnostics without replacing existing infrastructure. This reduces downtime and capital expenditure.

Remote Troubleshooting

With support for communication rates up to 230.4 Kbps, the cable enables fast data exchange over shorter distances (762 m). For longer trunklines up to 3048 m, the 57.6 Kbps rate ensures reliable connectivity. This flexibility supports both local and remote troubleshooting scenarios.

Cost-Effective Upgrade Path

Instead of purchasing new controllers or network adapters, facilities can use the 1784-U2DHP to extend the life of existing DH+ networks. The device draws power from the USB connection (5V DC, 125 mA), eliminating the need for external power supplies.

Installation & Setup Guidance

Before connecting the 1784-U2DHP, ensure the driver is properly installed on the computer. A unique COM port is created once the driver is installed. The cable has a 3-position switch for configuring the DH+ node address; the node address is set automatically upon first connection. One end of the cable has an USB connector, the other an 8-pin DIN connector. The DIN cable length is 2.44 meters, and the USB length is 0.61 meters. Always disconnect the cable from the USB port before changing the communication rate setting.

Maintenance & Reliability

The 1784-U2DHP is designed for Overvoltage Category II applications up to 2000 meters altitude without derating. It must be powered from a source compliant with SELV and PELV standards. The IP 30 enclosure protects against solid objects larger than 2.5 mm. LED indicators for USB, Power, and DH+ network provide real-time status; they blink red and green for events such as power supply, network activity, node duplication, and internal diagnostics. Inspect the cable periodically for damage and ensure the operating temperature stays between 0 and 55 degrees Celsius.

The Evolution of Industrial Connectivity

Industrial automation has long relied on robust, proprietary networks to ensure reliable communication between controllers and programming workstations. The Data Highway Plus (DH+) network, an Allen-Bradley protocol over RS485 wiring, became a standard for high-speed data transfer over long distances. As computing technology evolved, the need to bridge modern USB-equipped laptops with legacy DH+ networks grew critical. The Allen-Bradley 1784-U2DHP USB to Data Highway Plus cable directly addresses this need, offering a portable, industrial-grade solution that eliminates the need for older interface cards.

Compatibility & Integration

The 1784-U2DHP is compatible with PLC-5 processors (except Classic models PLC-5/10, PLC-5/12, PLC-5/15, and PLC-5/25) and SLC 5/04 processors. It supports three communication rates: 57.6 Kbps, 115.2 Kbps, and 230.4 Kbps, with corresponding maximum DH+ network lengths. The device replaces the 1784-PCMK communication adapter card and 1784-PCM6 communication cable, offering a direct USB connection.

Selection Guide & Purchasing Advice

When selecting the 1784-U2DHP, verify that your processor is supported (PLC-5 excluding Classic models, or SLC 5/04). Please verify current lifecycle status and availability with AutoDCSTech before ordering. AutoDCSTech offers this cable as part of its extensive inventory of industrial automation parts.