Rosemount 2051CD2A02A1AS3I1M5 Pressure Transmitter – 2051 Series

Rosemount 2051CD2A02A1AS3I1M5 405PS100N065D3H — Differential Pressure Transmitter in the Process Control Loop

The Rosemount 2051CD2A02A1AS3I1M5 405PS100N065D3H is a fully configured differential pressure transmitter assembly from Emerson’s Rosemount 2051 platform — one of the most widely deployed DP measurement instruments in continuous process industries. This unit ships as a complete, manifold-integrated assembly: the 2051CD2A02A1AS3I1M5 transmitter body mated to a 405PS100N065D3H three-valve integral manifold, ready for direct installation on standard 65 mm center-to-center DP taps.

In a process control loop, this transmitter occupies the field measurement layer. It converts differential pressure — generated across an orifice plate, venturi, annubar, or hydrostatic column — into a calibrated 4–20 mA HART signal. That signal feeds the DCS or PLC input card, where the engineering unit conversion, alarm logic, and PID setpoint calculation occur. The accuracy and long-term stability of this measurement directly determine the quality of the control action downstream. A transmitter that drifts 0.2% per year on a custody transfer flow loop introduces compounding fiscal error; the 2051CD’s ±0.04% reference accuracy and ±0.1% URL/5-year stability specification address this at the hardware level.

The CD2 capsule range (0.025 to 250 inH₂O / 0.062 to 62.3 kPa) covers the majority of standard orifice-plate flow applications and open-tank level measurements without requiring a range change. The 316L SST diaphragm (M5 option) handles mildly corrosive process fluids including dilute acids, brines, and hydrocarbon condensates. The dual-compartment aluminum housing (S3) physically separates the sensor electronics from the field wiring compartment, reducing the risk of moisture ingress into the signal conditioning board during cable entry work.

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Technical Parameters

Hardware Logical Analysis

Capacitance-Based Sensing Cell Architecture
The 2051CD uses a differential capacitance sensing cell. The process diaphragm deflects under applied differential pressure, shifting the capacitance ratio between two reference plates embedded in the fill-fluid cavity. The ASIC on the signal conditioning board converts this capacitance delta into a linearized digital value, which is then D/A converted to the 4–20 mA output. This architecture eliminates the mechanical linkages and strain gauges found in older piezoresistive designs, removing a primary failure mode in high-vibration installations.

EMC Design and NAMUR NE 21 Compliance
The electronics module is enclosed within a Faraday-shielded compartment inside the dual-compartment housing. The signal conditioning board carries transient suppression diodes on the loop terminals and a common-mode choke on the HART communication line. This design meets NAMUR NE 21 requirements for electromagnetic compatibility in industrial environments — specifically, the transmitter output remains within ±1% of span during conducted RF interference at 10 V/m field strength across the 80 MHz to 1 GHz band. In practice, this means the transmitter can be installed adjacent to variable-frequency drives and high-current motor starters without requiring additional shielding conduit.

Overpressure Protection Mechanism
The CD2 capsule incorporates a mechanical overpressure stop. When one-sided static pressure exceeds the differential range, the sensing diaphragm contacts a rigid backup plate machined into the capsule body, preventing permanent deformation. The transmitter recovers to within specification after the overpressure event is cleared. This is a critical design feature for applications where process isolation valves may be opened in the wrong sequence during commissioning or maintenance — a common field scenario that destroys unprotected DP cells.

HART Communication Layer
The A02 output option implements HART 5 and HART 7 simultaneously. The FSK signal is superimposed on the 4–20 mA loop at 1,200 baud. This allows a HART communicator or AMS Device Manager to read the transmitter’s diagnostic registers, perform remote ranging, and retrieve the sensor temperature — all without interrupting the primary 4–20 mA process signal. The HART burst mode capability allows the transmitter to autonomously publish process variable data at configurable intervals, supporting HART-IP gateway architectures without polling overhead.

Integral Manifold Mechanical Interface
The 405PS100N065D3H manifold uses a direct-mount interface that eliminates the impulse tubing runs between the manifold and transmitter body. The 65 mm center-to-center bolt pattern matches the standard IEC 61518 / ANSI/ISA 7.3 coplanar flange pattern. The PTFE valve packing (H suffix) provides a lower breakout torque than graphite packing, which is relevant in applications where the equalizing valve must be operated frequently during calibration checks. The 100 bar body rating provides a 4:1 safety factor over the CD2 capsule’s 25 bar maximum differential range.

System Integration Benefits

• Direct DCS Compatibility: The 4–20 mA HART output maps directly to standard AI card input ranges (1–5 V or 250 Ω burden) on Emerson DeltaV, Honeywell Experion, ABB 800xA, Yokogawa CENTUM VP, and Siemens PCS 7 — no signal conditioning module required in most installations.
• Remote Configuration Without Loop Interruption: HART secondary variable access allows engineers to read sensor temperature, percent of range, and loop current simultaneously with the primary DP measurement, supporting predictive maintenance workflows without process shutdown.
• Reduced Commissioning Time: The factory-calibrated output and pre-assembled manifold eliminate on-site zero/span calibration in most cases. The transmitter ships with a calibration certificate traceable to NIST standards, satisfying most plant QA requirements at first installation.
• Deterministic Alarm Response: The transmitter’s configurable high/low saturation output levels (3.6 mA and 21.0 mA by default, adjustable per NAMUR NE 43) allow the DCS to distinguish between a failed transmitter and a genuine process excursion — a distinction that is critical for safety instrumented system (SIS) logic solver inputs.
• SIL 2 Functional Safety Pathway: With the SIS option, the 2051CD is assessed per IEC 61508 for use in SIL 2 safety functions. The hardware fault tolerance and safe failure fraction data are published in the Rosemount 2051 Safety Manual, enabling direct use in SIL verification calculations without additional analysis.
• Coplanar Manifold Footprint: The integral 405 manifold reduces the installation envelope compared to traditional 5-valve remote-seal arrangements. This is particularly relevant in offshore topsides and modular skid packages where structural steel weight and space are constrained.
• Long Recalibration Interval: The ±0.1% URL/5-year stability specification supports extended calibration intervals under IEC 61511 and ISA-84 maintenance strategies, reducing the frequency of process interruptions for instrument calibration.
• AMS and PACTware Asset Management Integration: The transmitter’s HART DD (Device Description) file is registered in the HART Communication Foundation library. AMS Device Manager and PACTware with the Rosemount DTM can read the full diagnostic parameter set — including sensor temperature, electronics temperature, and loop current — enabling condition-based maintenance scheduling.

Quality Assurance & Global Logistics

Genuine Rosemount Origin
Every unit supplied through siemensplc.com is sourced from verified industrial distribution channels. The 2051CD2A02A1AS3I1M5 405PS100N065D3H carries Rosemount’s original factory nameplate, serial number, and model code label. Serial numbers are cross-referenced against Emerson’s product registration database prior to listing. Units with tampered nameplates, re-stamped serial numbers, or non-original packaging are rejected at intake inspection.

Pre-Shipment Inspection Protocol
Each unit undergoes a structured pre-shipment check: physical housing inspection for cracks, dents, and thread damage; nameplate and label legibility verification; connector and process flange thread gauge check; and a powered loop test confirming 4 mA at zero input and 20 mA at full-scale input using a precision decade resistance box and calibrated current meter. Units that fail any check are quarantined and not shipped.

Packaging and Export Documentation
Units are packed in anti-static foam inserts within double-wall corrugated cartons. Each shipment includes a commercial invoice with HS code classification, packing list, certificate of origin (China), and the pre-shipment inspection report. Material certificates for the 316L SST wetted parts are available upon request. A 12-month warranty against manufacturing defects is provided from the date of shipment.

Logistics from Xiamen, China
Our warehouse is located in Xiamen, Fujian Province — a major port city with direct access to DHL, FedEx, and UPS international express networks. Standard export processing time is 1–2 business days after payment confirmation. DHL Express delivery to Western Europe and North America typically completes in 3–5 business days door-to-door. Southeast Asia destinations are typically 2–3 business days. For large-volume orders, LCL and FCL sea freight options are available through Xiamen Port with competitive transit times to major global ports. All shipments are tracked end-to-end, with tracking numbers provided within 24 hours of dispatch.

Contact Information

Email: [email protected]
WhatsApp: +86 18359268345
Web: siemensplc.com
Location: Xiamen, China
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