Rosemount 644 Temperature Transmitter Decoder Skip to main content
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Rosemount 644 Temperature Transmitter Decoder

Paste a 644 head, field, or rail model code and read supported PDS rows while sensor, certification, SIS, Fieldbus, configuration, installation, and qualified-review gaps stay visible.

Field guide: Rosemount 2051 Ordering Code Guide: 2051C, 2051T, 2051G and the 2051-vs-3051 Decision

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A decoder for supported Rosemount 644 Temperature Transmitter model-code rows. The local parser reads transmitter type, output, and option adders from Emerson PDS 00813-0100-4728 Rev WH plus rail rows from PDS 00813-0300-4728 Rev AA. It is a reference prompt only: it does not replace the current Emerson configurator, quote, product-certification label, QSG/manual, configuration data sheet, live device configuration, sensor/thermowell facts, Fieldbus or PROFIBUS host setup, local code/AHJ review, or qualified instrumentation and safety review. The 644 model code does not prove sensor type, RTD/thermocouple curve, range, span, damping, alarm settings, SIS suitability, hazardous-area installation, host files, loop wiring, calibration, or commissioning status.

Pro Tip: Use the warning rows as review prompts. FOUNDATION Fieldbus (F) and PROFIBUS PA (W) are only offered on the single-sensor head mount (type H) in the PDS rows this parser supports, and Hot Backup (DC) depends on a dual-sensor build plus correct sensor wiring and configuration. Confirm the final model and live setup against current Emerson documents and qualified project review before purchase, installation, commissioning, or field changes.

Decode the higher-feature 3144P (dual sensor, Hot Backup, X-well) when the 644 is not enough

Rosemount 3144P Decoder →

Decode the 848T multi-input transmitter for high point-count temperature installations

Rosemount 848T Decoder →

Decode the pressure side of the same Emerson ecosystem

Rosemount 3051 Decoder →

Relate the configured temperature span to expected 4-20 mA output on a HART loop

4-20 mA Signal Helper →

How It Works

  1. Start with the 644 prefix

    Begin the code with 644. The decoder reads the transmitter type and output next, then treats everything else as option adders.

  2. Read the transmitter type

    Position 1 is the type: H head single, S head dual, F field single, D field dual, R rail single, T rail dual. This single character carries both the form factor (head / field / rail) and the sensor count (single / dual).

  3. Read the output

    Position 2 is the output: A HART 4-20 mA, F FOUNDATION Fieldbus, W PROFIBUS PA. Fieldbus and PROFIBUS are single-sensor-head only; the decoder warns if they appear on any other type.

  4. Walk the option string

    Diagnostics, enclosure, bracket, display, software, performance, alarm level, line filter, sensor trim, calibration, custody-transfer, safety, shipboard, transient, cable gland, conduit connector, HART revision, assemble-to, warranty, and approval rows are matched by longest match. Treat the row and page as a prompt for current-source review, not order proof.

  5. Note that the sensor is not in the code

    The decoder makes explicit that the RTD/thermocouple type, range, and span are configured separately, not encoded. Use option XA, the Configuration Data Sheet, the sensor model, and live device configuration to identify the actual measurement.

  6. Read the constraint warnings

    Warnings fire only on real conflicts: Fieldbus/PROFIBUS on a non-H type, Hot Backup (DC) on a single-sensor type, a field-mount enclosure (D1/D2) on a non-field type, or the RK rail version on a non-rail type.

  7. Export the review prompt

    PDF and CSV export package the same decoded rows, warnings, assumptions, and residual source gaps so the current Emerson/project review can be replayed.

Built For

  • Maintenance tech decoding a 644 head-mount nameplate as a spare-parts review prompt without assuming the installed sensor or configuration
  • Reliability engineer checking whether a dual-sensor 644 row is present before reviewing Hot Backup wiring and configuration records
  • Project engineer flagging Fieldbus or PROFIBUS rows for host, segment, device-file, and commissioning review
  • Planner decoding a rail-mount 644 (type R or T) and keeping the separate Rev AA rail PDS boundary visible
  • Buyer listing QT, approval, enclosure, and certificate rows for Emerson representative and project-spec review
  • Estimator bulk-decoding 644 codes from an instrument index to pull out mount style and output
  • Inspector flagging custody-transfer, calibration, and configuration rows for the current project records instead of treating the model code as compliance proof

Features & Capabilities

Head, field, and rail in one decoder

Types H/S/F/D come from the head/field PDS; rail types R/T and the RK HART 7 version come from the separate rail PDS. Both are decoded under the single 644 model number with rail-specific rows cited to the rail document.

Output-vs-type constraint enforcement

FOUNDATION Fieldbus and PROFIBUS PA outputs are flagged when ordered on anything but the single-sensor head (type H), because the PDS restricts them there. Dual-sensor, field, and rail builds are HART only.

Hot Backup needs dual sensor

The DC diagnostics option (Hot Backup and sensor drift alert) is flagged unless the transmitter type is dual-sensor (S head or T rail). This is the most common 644 spec mistake and the decoder catches it.

Sensor-not-in-code honesty

The decoder does not pretend to know the measurement. It states plainly that the sensor type, range, and span are configured separately and points at the assemble-to option and the Configuration Data Sheet.

Enclosure and approval review prompts

Enclosure, cable, conduit, approval, QT/FMDA, and shipboard rows are decoded with page prompts but still require the current certificate, label, QSG/manual, ambient/process limits, installation drawing, local code, and AHJ review.

Confidence-labeled rows with source citations

Supported rows carry their local PDS page and a confidence label. Rail rows are explicitly tied to the separate rail PDS so the two-document source boundary is visible.

PDF and CSV export

Page-break-safe PDF and CSV export include decoded rows, constraint warnings, source-boundary warnings, assumptions, and residual source gaps.

Tripwire test suite

Canonical integrity, golden-path, negative-path, source-page coverage, hydration hardening, source-pointer, and report/PDF boundary tests run on every change.

Comparison

Transmitter type Mount Sensors Outputs available Hot Backup?
H Head Single HART, Fieldbus, PROFIBUS PA No
S Head Dual HART only Yes (DC)
F Field Single HART only No
D Field Dual HART only Yes (dual), DC per PDS is S/T
R Rail Single HART only No
T Rail Dual HART only Yes (DC)

References

  1. Emerson Rosemount 644 Temperature Transmitter Product Data Sheet, 00813-0100-4728, Rev WH, February 2026
  2. Emerson Rosemount 644 Rail Mount Temperature Transmitter Product Data Sheet, 00813-0300-4728, Rev AA, December 2021
  3. Emerson Rosemount 644 Temperature Transmitter Quick Start Guide, 00825-0200-4728, Rev LH, March 2026
  4. Emerson Rosemount 644 Reference Manual, 00809-0200-4728, Rev SF, January 2023
  5. IEC 61508 - Functional safety of electrical/electronic/programmable electronic safety-related systems (for the QT safety certification)

Frequently Asked Questions

The PDS restricts FOUNDATION Fieldbus (F) and PROFIBUS PA (W) to the single-sensor head mount (type H). Dual-sensor (S/D/T), field-mount, and rail-mount builds are HART (A) only. If you need a digital fieldbus protocol and more than one sensor on one device, that is a 3144P or an 848T job, not a 644.
Hot Backup (option DC) requires a dual-sensor transmitter type: S (head) or T (rail), and the actual failover behavior depends on sensor wiring, configuration, diagnostics, and maintenance records. A single-sensor 644 has nothing to fail over to. The decoder fires a constraint warning when DC appears without a dual-sensor type.
The model code does not say. The 644 sensor type, range, and span are configured on the device, not encoded in the order code. Pull the Configuration Data Sheet (ordered with option C1) or, if the sensor was assembled at the factory (option XA), read the sensor model string. The decoder states this explicitly rather than guessing.
Rail mount is a separate, older PDS (00813-0300-4728 Rev AA, December 2021). Types R and T and the RK HART 7 version come from that document. Rail units do not take the head/field enclosures or shipboard/conduit options. The decoder cites rail-specific rows to the rail PDS so the sourcing is clear.
On the 644 rows this parser supports, custody transfer (option D4 MID, Europe) is a HART-side prompt. Protocol-specific feature sets differ between HART and Fieldbus builds; decode the exact code and verify the current PDS/configurator, certification records, and project requirements rather than assuming a feature carries across protocols.
The 644 is the workhorse single/dual-point transmitter. The 3144P is the higher-feature field-mount transmitter: it adds X-well surface measurement, a richer dual-input feature set (differential, average, first-good, two-independent), and tighter accuracy options. Step up to the 3144P when you need those; the 644 covers the majority of plant temperature points.
Disclaimer: This decoder reads supported Rosemount 644 model-code rows against public Emerson source pointers. Output protocol, diagnostics, certificates, rail options, and availability can change by revision, region, and mounting style, and the model code does not encode the sensor, range, span, damping, alarm settings, host setup, installation, or live configuration. Use this tool as a source-aware review prompt only; verify the final model number, certificate, QSG/manual requirements, configuration, installation, commissioning, and safe-work controls with Emerson and qualified project review.

Guides for this job

Shops & Outbuildings

Rosemount 2051 Ordering Code Guide: 2051C, 2051T, 2051G and the 2051-vs-3051 Decision

Plain-language guide to reading supported 2051C/T/G model-code rows with PDS page citations while keeping ordering, certification, hazardous-area, configuration, WirelessHART, process-compatibility, installation, and qualified-review gaps explicit.

Read Guide →
Shops & Outbuildings

Rosemount 644 Ordering Code Guide: Head, Field, Rail and the Fieldbus / Hot Backup Constraints

Plain-language guide to supported Rosemount 644 head, field, and rail model-code rows, why the sensor is not encoded, and where Fieldbus, Hot Backup, certification, configuration, installation, and qualified-review boundaries remain.

Read Guide →
Shops & Outbuildings

Rosemount 3144P Ordering Code Guide: Single vs Dual Sensor, X-well, and the HART / Fieldbus Split

Plain-language guide to reading supported Rosemount 3144P model-code rows while keeping current Emerson configurator, sensor configuration, X-well, hazardous-area, SIS, installation, and commissioning gaps visible.

Read Guide →
Shops & Outbuildings

Rosemount 848T Ordering Code Guide: Channel Count, the S002 Cert Trap, and the Wireless Build

Plain-language guide to supported Rosemount 848T Rev SD rows while keeping channel-map, S002, Fieldbus host, WirelessHART network, configuration, certification, and installation review gaps visible. Companion to the Rosemount 848T Multi-Input Temperature Decoder.

Read Guide →

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