Fieldbus and HART Together: Why TREXLFPKLWS3S Is the Only Handheld You Need-abplccenter.com

If your plant runs both HART and FOUNDATION Fieldbus devices, you have likely juggled two different communicators – or used a basic HART handheld and hoped the FF segment never acted up. Emerson's TREXLFPKLWS3S changes that.

This model is the "fully loaded" Trex: it includes the Device Communicator Plus module with built-in loop power for HART and a dedicated FF power plug. Plus, it ships with the Fieldbus Diagnostics app and 3 years of standard support.

Trex connected to Fieldbus device

What Makes the "Plus" Module Different?

Standard Trex models (like the CHPKLWS1S) can communicate with HART devices but cannot power them. The TREXLFPKLWS3S can power a HART device in a bench setup (3-22.5 mA) and power a FOUNDATION Fieldbus device (up to 38 mA). This means:

You can configure a transmitter before it is installed – no need for a separate power supply.
You can isolate a device from the loop and test it without affecting the process.
You can troubleshoot FF segments by powering them directly from the Trex.

Fieldbus Diagnostics: A Game Changer

FF segments are notoriously tricky to validate. With the Fieldbus Diagnostics app, you can:

Measure network DC voltage and average noise.
Detect power supply problems.
Verify segment health before connecting devices.

No more guessing if the problem is the wiring, the power conditioner, or the device.

Fieldbus Diagnostics interface

Real-World Use Cases

Greenfield project pre-commissioning – Configure FF and HART devices on the bench before I/O and power are ready. Load configurations via Wi-Fi to AMS later.
FF segment troubleshooting – Isolate a problem segment, power it from Trex, and check device responses without involving the host system.
Valve diagnostics on both protocols – Use ValveLink Mobile with Fisher FIELDVUE DVCs over HART or FF. Perform signature tests without pulling valves.

Cost of Ownership: Why 3-Year Support Matters

The TREXLFPKLWS3S includes 3-year Standard Support out of the box. That means:

Technical support from Emerson (no extra cost for 3 years)
Software and DD library updates (automated via Upgrade Studio)
Peace of mind – the communicator stays current without annual renewal hassles

Is TREXLFPKLWS3S Right for You?

If you work with both HART and FF devices – especially in new projects or maintenance-heavy FF segments – this is the model to choose. The built-in power capability alone pays for itself in time saved hunting for a bench supply.

Ready to see it in action? View the TREXLFPKLWS3S product details → or contact our team for a demo.