Emerson 375, 475 and AMS Trex Upgrade Guide: Trex 2 Decoder
If you still carry an Emerson 375, a 475 or an original AMS Trex, you are working with a discontinued tool. Emerson's current handheld is the AMS Trex 2 Device Communicator, and its model numbers start with TREX2. This guide walks through the four generations, shows what changed at each step, explains every position in a TREX2 model code using units we have recently received, and tells you which Trex 2 to order to replace the communicator you have now.
HKXYTECH supplies brand-new, original Emerson communicators only. We do not sell used or refurbished units.
Quick answers
What replaced the Emerson 475 Field Communicator? Emerson discontinued the 475 Field Communicator and supported existing units only through October 2020. Its successor was the AMS Trex Device Communicator. The original AMS Trex has since been superseded and is also discontinued, so the current replacement is the AMS Trex 2 Device Communicator, whose model numbers start with TREX2. Choose by protocol: application code H gives HART, and F gives HART plus FOUNDATION Fieldbus.
How do you read an AMS Trex 2 model number such as TREX2CHPKLWS1S? Read it left to right. TREX2 is the Trex 2 platform. C is the Device Communication Module (L would be the Plus module, with ammeter and loop power). H is the HART application (F adds FOUNDATION Fieldbus). P is the rechargeable Li-ion power module. KL is the intrinsically safe ATEX, CSA, CCC and IECEx approval (NA means no approval). W adds Wi-Fi and Bluetooth (9 means no radio). S1 is one year of Product Support, and the final S is the soft carrying case.
What is the difference between AMS Trex and AMS Trex 2? Trex 2 model numbers start with TREX2. Its wireless option pairs Wi-Fi with embedded Bluetooth, where the original Trex paired Wi-Fi with NFC. It moves to a faster platform: a quad-core processor, 4 GB of RAM and an Android 14-based operating system, against the original's 800 MHz processor and Windows Embedded Compact 2013. According to Emerson's Trex 2 user guide, Trex 2 communication modules are not interchangeable with original Trex modules and run only on the Trex 2 OS. A Trex 2 is a new unit, not an upgrade kit.
The Emerson handheld lineage: 375 → 475 → AMS Trex → AMS Trex 2
Each generation of Emerson handheld was replaced by the next. Here is the path, with only the dates Emerson itself has published:
- 375 Field Communicator – retired. Emerson describes the 475 as building "on the industry-leading technology of the 375 Field Communicator", and Emerson published a model number conversion chart from 375 to 475 codes. The 375 is discontinued; we do not quote a retirement date because we have not found one in an Emerson document.
- 475 Field Communicator – discontinued. Emerson's 475 data sheet (March 2020) carries the banner "PRODUCT DISCONTINUED". It states that the 475 "is no longer available for sale" and that existing communicators "will be supported through October 2020". Easy Upgrade subscriptions expired on 30 October 2020, and Emerson pointed 475 users to the AMS Trex.
- AMS Trex Device Communicator (first generation, model codes TREX…) – discontinued and superseded by Trex 2. The last data sheet we reference is dated November 2023.
- AMS Trex 2 Device Communicator (model codes TREX2…) – current. Emerson's Trex 2 data sheet is dated August 2026. Emerson describes it as the next generation of AMS Trex, "redesigned to operate on a modern, faster platform with improved accuracy and device connectivity including embedded Bluetooth".
In practice, wherever you start, the answer for a new purchase today is the same: order an AMS Trex 2. The rest of this guide shows how to pick the right TREX2 code.
Four generations compared
The table uses only figures from Emerson data sheets and user guides. Where Emerson's documents we reviewed give no figure, the cell says so; we have not filled gaps with estimates.
| 375 | 475 | AMS Trex (TREX) | AMS Trex 2 (TREX2) | |
|---|---|---|---|---|
| Status | Discontinued | Discontinued; support through Oct 2020 | Discontinued | Current |
| Protocols | Not reviewed | HART, FOUNDATION Fieldbus | HART, FOUNDATION Fieldbus | HART, FOUNDATION Fieldbus, Bluetooth devices |
| Processor | Not reviewed | 80 MHz Hitachi SH3 | 800 MHz ARM Cortex A8 / NXP | 1.2 GHz quad-core Cortex-A53 / NXP i.MX 8M Mini |
| RAM | Not reviewed | 32 MB | 512 MB DDR3 | 4 GB LPDDR4 |
| Storage | Not reviewed | 32 MB flash + 1 GB SD System Card | 2 GB NAND + 32 GB extended flash | 64 GB NAND flash |
| Operating system | Not reviewed | Not stated | Windows Embedded Compact 2013 | Custom Android 14 platform |
| Display | Not reviewed | 3.5 in. ¼ VGA colour touchscreen | 5.7 in. colour VGA resistive touchscreen | 5.7 in. colour VGA resistive touchscreen |
| Wireless | Not reviewed | Bluetooth, IrDA | Wi-Fi, NFC | Wi-Fi, Bluetooth Low Energy |
| Battery life (typical) | Not reviewed | 40 hours typical use | 8+ hours typical use | 8+ hours typical use |
| Weight | Not reviewed | approx. 0.75 kg with battery | approx. 1,330 g | approx. 1,330 g |
| Enclosure | Not reviewed | IP51 (from front) | IP54 | IP54 |
| Operating temperature | Not reviewed | –10 to +50 °C | –20 to +55 °C | –20 to +55 °C |
Two notes for buyers: - Wi-Fi on Trex 2: the Trex 2 user guide lists a known issue: the Wi-Fi radio is "temporarily disabled" and "will be enabled with a future OS update". Bluetooth is unaffected. If Wi-Fi sync to AMS Device Manager is essential to you, plan for a USB connection until Emerson's update is installed. - Warranty wording differs: the original Trex data sheet states 18 months against manufacturing defects. The Trex 2 data sheet states 12 months. Confirm the warranty terms that apply to your order with us before purchase.
How to read an AMS Trex 2 model number (TREX2…)
A Trex 2 model number is built from fixed positions followed by optional letters. From Emerson's AMS Trex 2 data sheet (August 2026):
| Position | Code | Meaning |
|---|---|---|
| Base | TREX2 | Base Trex 2 platform |
| Communication module | C | Device Communication Module (HART + FOUNDATION Fieldbus) |
| L | Device Communication Plus Module (HART, FF, ammeter, Power the Loop & Loop Diagnostics App) | |
| Applications | H | HART application |
| F | HART + FOUNDATION Fieldbus applications | |
| Power module | P | Rechargeable Li-ion power module |
| Certification | KL | ATEX, CSA (US/Canada), CCC and IECEx intrinsically safe (includes FISCO as applicable) |
| NA | No approval | |
| Radio | W | Wireless (Wi-Fi and Bluetooth) |
| 9 | None | |
| Support | S1 / S3 | Product Support, 1 or 3 years |
| P1 / P3 | Product Support + Repair, 1 or 3 years | |
| Options (multi-select) | S | Carrying case (soft) |
| R | Radar Master App | |
| W | WirelessHART Provisioning App |
Three details trip up buyers:
- The F is not a module. C and L are the hardware modules; H and F are application licences. On Trex 2, Emerson notes that FOUNDATION Fieldbus requires the F application licence, and that the C module itself is listed as HART + FOUNDATION Fieldbus hardware.
- The Plus module (L) is for loop work. It adds the built-in ammeter, the ability to power the loop, and loop diagnostics. Emerson states that it also comes with factory calibration of electrical measurements to NIST standards. If you commission on the bench or need to measure 4–20 mA without a separate meter, choose L.
- Option letters at the end are easy to drop. A trailing S (case), R (Radar Master) or W (WirelessHART Provisioning) changes what is in the box. Always quote the full code.
Worked examples from units we have received
These are real TREX2 codes from our recent arrival notices. Click any one for the arrival page.
| Model code | Decoded |
|---|---|
| TREX2CHPKLWS1R | Trex 2 · C module · HART · Li-ion · IS (KL) · Wi-Fi/Bluetooth · 1-yr Product Support · Radar Master App |
| TREX2CFPKLWS1R | Trex 2 · C module · HART + FF · Li-ion · IS · Wi-Fi/Bluetooth · 1-yr Product Support · Radar Master App |
| TREX2LHPKLWS1R | Trex 2 · Plus module · HART · Li-ion · IS · Wi-Fi/Bluetooth · 1-yr Product Support · Radar Master App |
| TREX2LFPKLWS1R | Trex 2 · Plus module · HART + FF · Li-ion · IS · Wi-Fi/Bluetooth · 1-yr Product Support · Radar Master App |
| TREX2LFPKL9P3S | Trex 2 · Plus module · HART + FF · Li-ion · IS · no radio · 3-yr Support + Repair · soft case |
| TREX2LHPKL9P3S | Trex 2 · Plus module · HART · Li-ion · IS · no radio · 3-yr Support + Repair · soft case |
| TREX2CHPKL9P3S | Trex 2 · C module · HART · Li-ion · IS · no radio · 3-yr Support + Repair · soft case |
| TREX2CFPKL9P3S | Trex 2 · C module · HART + FF · Li-ion · IS · no radio · 3-yr Support + Repair · soft case |
| TREX2CFPKLWP3S | Trex 2 · C module · HART + FF · Li-ion · IS · Wi-Fi/Bluetooth · 3-yr Support + Repair · soft case |
Availability changes, so please ask us for current quantities and delivery before you order.
How to read an original AMS Trex model number (TREX…)
You will still see first-generation codes on existing equipment lists and spare-parts records. From Emerson's AMS Trex data sheet (November 2023):
| Position | Code | Meaning |
|---|---|---|
| Base | TREX | Base Trex platform |
| Communication module | C / L | Device Communicator module / Device Communicator Plus module |
| Applications | H / F | HART / HART + FOUNDATION Fieldbus |
| Power module | P | Rechargeable Li-ion power module |
| Certification | KL / NA | ATEX, CSA (US/Canada) and IECEx intrinsically safe / no approval |
| Radio | W / 9 | Wireless (Wi-Fi and NFC) / none |
| Support | S1, S3 / P1, P3 | Standard Support / Premium Support (adds accidental-damage coverage), 1 or 3 years |
| Options | S, R, W | Carrying case, Radar Master App, WirelessHART Provisioning App |
For example, TREXCHPKLWS1S is an original Trex with the standard module, HART, IS approval, wireless, one year of Standard Support and a carrying case. To move a TREX code to Trex 2, keep the same letters for module, application, certification and radio, and change the prefix to TREX2. Note that the radio W changes from Wi-Fi + NFC to Wi-Fi + Bluetooth, and the support codes S and P change their meaning slightly (see above).
Which Trex 2 replaces my 375, 475 or Trex?
The mapping below is our editorial guidance for choosing a like-for-like Trex 2. It is not an official Emerson conversion chart. Confirm the final code with us before ordering.
Step 1: decode the code on your current unit
475 codes follow this pattern (from Emerson's 475 ordering table): 475 + protocol (H = HART, F = HART + FF) + battery (P = Li-ion) + charger (1 = included, 9 = not included) + language (E = English, C = Chinese, etc.) + certification (KL = IS, NA = none) + Easy Upgrade (U = 3-year, 9 = none) + GM (graphics and configuration management) + Bluetooth (T = yes, 9 = no) + options (A = spare battery, S = rubber boot with stand). For example, 475HP1EKLUGMT is a HART-only, intrinsically safe, English 475 with charger, Easy Upgrade and Bluetooth.
375 codes are shorter, for example 375HP1EKLU. Emerson's 375-to-475 conversion chart maps 375HP1EKLU to 475HP1EKLUGMT. Convert your 375 code to its 475 equivalent first, then use the table below.
Step 2: map each option to Trex 2
| On your 375 / 475 / Trex | Choose on Trex 2 |
|---|---|
| H (HART only) | H |
| F (HART + FOUNDATION Fieldbus) | F |
| KL (intrinsically safe) | KL |
| NA (no approval) | NA |
| 475 Bluetooth T, or Trex W | W (Wi-Fi + Bluetooth) |
| 475 Bluetooth 9, or Trex 9 | 9 (no radio) |
| 475 Easy Upgrade U, or Trex S1/S3/P1/P3 | S1 / S3 (Product Support) or P1 / P3 (Product Support + Repair) |
| You need to power the loop or measure mA | L (Plus module) instead of C |
| 475 option S (rubber boot), or Trex S (case) | S (soft carrying case) – a case, not a boot |
Step 3: start from Emerson's typical models
Emerson's Trex 2 data sheet lists three typical configurations, which cover most replacement orders:
- Basic HART: TREX2CHPKLWS1S
- Typical HART: TREX2LHPKLWP1S
- Typical HART + FOUNDATION Fieldbus: TREX2LFPKLWP3S
A plant that used 475FP1EKLUGMT for HART and Fieldbus work in hazardous areas would normally move to a TREX2 with F, KL and W. Pick C or L depending on whether technicians need loop power and the ammeter.
What does not carry over
Trex 2 is a new handheld. Emerson's Trex 2 user guide states that Trex 2 communication modules are not interchangeable with Trex 1 modules. We have not seen Emerson guidance confirming that 375 or 475 accessories, leads or stored configurations transfer to Trex 2, so plan to use the accessories supplied with the new unit. Emerson lists the standard box contents as AC adapter, USB cable, lead set with connectors, hand strap, approvals and certifications guide, and Get Started flyer.
Still need a 475?
Some sites must keep an identical 475 for procedure or approval reasons. The 475 is discontinued and Emerson support ended in October 2020. HKXYTECH can supply brand-new, original 475 units while stock lasts. For long-term use and current device descriptions, we recommend the matching AMS Trex 2.
Before you order: buyer checklist
- Quote the full model code. Include every suffix letter, for example TREX2LFPKLWP3S, not "Trex 2 HART/FF".
- Confirm hazardous-area approval. KL for intrinsically safe use; NA only for safe areas.
- Check wireless approval for your country. Emerson notes that the wireless option is available only where spectrum approval has been obtained.
- Choose support length. Product Support covers technical support and software updates. Product Support + Repair adds coverage against accidental damage.
- Confirm quantity, destination and required documents. Tell us the delivery country and any paperwork your project needs, so we can confirm delivery time before you place the order.
How we keep it genuine
HKXYTECH sells only brand-new, original branded products. We never sell used or refurbished stock. When you order a Trex 2 from us, ask for photos of the nameplate showing the exact TREX2 model code and serial number, the outer carton label and the packing list before shipment. Emerson states that applications such as ValveLink Mobile are available at no charge "once the AMS Trex unit is activated"; ask us about activation when you place your order.
FAQ
Is the Emerson 475 still supported? No. Emerson's 475 data sheet says existing communicators were supported through October 2020, and Easy Upgrade subscriptions expired on 30 October 2020.
Is the original AMS Trex still the current model? No. The original AMS Trex (TREX… codes) is discontinued. Emerson's current model is the AMS Trex 2 (TREX2… codes).
Can I use my original Trex communication module on a Trex 2? No. Emerson's Trex 2 user guide states that Trex 2 communication modules are not interchangeable with Trex 1 modules and are supported only on the Trex 2 OS.
Which protocols does Trex 2 support? Emerson lists HART, FOUNDATION Fieldbus and Bluetooth-enabled devices. FOUNDATION Fieldbus requires the F application code.
Do I need the Plus (L) module? Choose L if you need to power a device from the communicator, measure loop current with the built-in ammeter, or run loop diagnostics. Otherwise the C module communicates on externally powered loops and segments.
Does HKXYTECH sell used or refurbished communicators? No. We supply brand-new, original units only.
Related pages
- AMS Trex communicators and AMS Trex overview
- 475 Field Communicator and 475 overview
- 375 Field Communicator and 375 overview
- What is a HART communicator? and What is the HART protocol?
- Other brands: Yokogawa BT200, Yokogawa FieldMate, Honeywell MCT404, ABB DHH805
Get a quote
Send us the full model code you need (for example TREX2LFPKLWP3S), or the code on your current 375, 475 or Trex if you want us to suggest the matching Trex 2. Add the quantity and destination country, and we will reply with price and delivery confirmation for brand-new, original units. Contact HKXYTECH.
Sources: Emerson AMS Trex 2 Device Communicator data sheet (August 2026); Emerson AMS Trex Device Communicator data sheet (November 2023); Emerson AMS Trex 2 Device Communicator user guide; Emerson 475 Field Communicator data sheet (March 2020); Emerson "475 has retired!" flyer; Emerson AMS Trex product page; Emerson 375-to-475 model number conversion chart; Emerson 475 ordering information as reproduced by TEquipment.
Contact
Email: becky@hkxytech.com
Mob: +86 15972186287
