YJINGRUI USB HART Modem USB to HART Interface

The YJINGRUI USB HART Modem is a compact USB‑to‑HART interface that lets a PC communicate, power, and configure HART field transmitters with an integrated loop resistor for plug‑and‑play diagnostics.

This device converts a standard USB‑A connection into a HART two‑wire interface, supporting popular brands such as Rosemount, ABB, Vega and other HART‑enabled instruments. It’s designed for commissioning, calibration, service and data acquisition tasks where you need a reliable PC connection to loop‑powered transmitters. The modem includes selectable modes and a built‑in 270 Ω loop resistor option so you can connect quickly without extra wiring or external resistors.

How does the YJINGRUI modem link my PC to HART instruments?

The modem uses a USB‑A port on your computer and provides a polarity‑insensitive two‑wire HART clip connection. Install the supplied driver (or download the current version online) and run your HART software to exchange commands, read diagnostics and upload configurations. It behaves like a standard serial HART interface once the driver is installed.

• USB‑A interface for simple plug‑in connectivity
• Polarity‑insensitive two‑wire test clips for easy field hookup
• Compatible with common HART software suites once drivers are loaded

Will it power the loop and replace an external resistor?

Yes — the unit offers selectable operating modes including a built‑in 270 Ω loop resistor option and a 24 VDC mode for powering transmitters. That built‑in resistor removes the need to add a separate resistor when performing many commissioning and calibration tasks, simplifying field setups. Selectable modes help match the modem to the instrument and software you’re using.

• Option modes: 24 VDC/270 Ω, Normal, and 270 Ω
• Built‑in resistor eliminates extra hardware in many cases
• Useful for single‑device bench tests and on‑site commissioning

Which operating systems and instruments are supported?

The modem supports a wide range of Windows versions, including Windows 98/2000/XP/7/8/10/11, and will work with HART transmitters from manufacturers like Rosemount, ABB and Vega. Drivers are supplied on CD and can also be downloaded from the web if your computer doesn’t automatically recognize the device. Ensure your HART software is compatible to complete the communication setup.

• Windows compatible: XP through Windows 11 (also legacy versions listed)
• Works with Rosemount, ABB, Vega and other HART devices
• Driver available on CD or via internet download for updates

How do I use the modem safely and reliably in the field?

Connect the modem’s USB end to your PC and attach the HART clips to the two‑wire transmitter leads, checking clip polarity isn’t required. Choose the correct mode depending on whether you need loop power or only signaling, then open your HART configuration software and select the modem’s COM port. Regularly update drivers and follow your plant’s electrical safety procedures when connecting to live loops.

• Plug USB into PC, attach two test clips to the transmitter leads
• Select required mode (24 VDC/270 Ω, Normal, or 270 Ω)
• Open HART software and choose the modem’s COM port

Who is this for: field technicians, instrument engineers and commissioning teams who need a portable, straightforward USB interface to HART instruments. It’s particularly useful for maintenance crews performing calibration, troubleshooting or data collection on Rosemount, ABB, Vega and other HART devices, and for engineers who want a compact tool that eliminates extra resistors during many routine tasks.