Description
Application Scenarios:
A refinery was replacing a failed DP transmitter on a crude preheat train, measuring differential pressure across a heat exchanger bundle to detect fouling. The impulse piping, manifolds and mounting had been built two decades earlier around a traditional flange with 1/4-18 NPT process connections on 2-1/8 inch centres. The instrument team’s first choice — a standard Coplanar unit — would have meant reworking the impulse legs and the bracket, which on a live header meant a hot-work permit, a scaffold, and a window that only came around at the next turnaround.
Specifying the 3051CD2A02A1AH2E5M5 removed all of that. Materials-of-construction code 0 combined with alternate flange code H2 delivers exactly that traditional flange geometry: 316 SST body, SST drain and vent, 1/4-18 NPT process connections at IEC 61518 standard centres, with adapters available to rotate connection centres to 2.00, 2.126 or 2.25 inches. The transmitter bolted to the existing impulse piping, the mounting bracket pattern matched, and the loop was re-ranged over HART in a single shift.
Once commissioned, the value moved from installation to operations. The exchanger had been cleaned on a fixed 18-month cycle regardless of condition. With the 3051CD2A02A1AH2E5M5 trending DP at 0.04% of span reference accuracy and holding that reading stable for years, the team could finally see the fouling curve and move to condition-based cleaning — extending intervals where the crude was clean and catching the bad slugs early. The second pain point it solved was diagnostics: on a unit with an LCD display, a technician standing at the exchanger can read DP, check the loop and confirm the device health without walking back to the marshalling cabinet.
Parameter:
| Main Parameters | Value/Description |
|---|---|
| Product Model | 3051CD2A02A1AH2E5M5 |
| Manufacturer | Rosemount — Emerson Automation Solutions |
| Product Category | Differential pressure transmitter (3051C Coplanar platform, DP measurement type) |
| Measurement Range | Range 2: -250 to +250 inH2O (-621.60 to +621.60 mbar); minimum span 1.67 inH2O (4.15 mbar) — the smallest span you can calibrate without losing accuracy class |
| Output Signal | 4-20 mA with digital signal based on HART protocol (two-wire, loop powered); HART Revision 5 default, field-selectable to Revision 7 |
| Reference Accuracy | ±0.04% of span (Ranges 2-4, for spans below 10:1); total installed performance 0.14% of span |
| Rangedown | Up to 150:1 — one sensor covers a wide band of operating conditions without a hardware change |
| Long-Term Stability | ±0.2% of URL for 10 years per the classic published specification; Emerson’s current data sheet states 0.1% of URL for up to 12 years |
| Process Wetted Materials | Isolating diaphragm 316L SST; O-ring glass-filled PTFE; sensor fill fluid silicone; flange, drain and vent 316 SST |
| Process Connection | Traditional flange (option H2), 1/4-18 NPT, connection centres to IEC 61518; adapters give 2.00 / 2.126 / 2.25 in (51 / 54 / 57 mm) centres and 1/2-14 NPT |
| Static Pressure and Overpressure | Operates to specification between 0.5 psia and 3626 psig (250 bar) static line pressure; Ranges 2-5 overpressure limit 3626 psig (4500 psig with option P9) |
| Electrical | External power required; 10.5-42.4 V dc at no load (42.4 V limit applies for CSA); maximum loop resistance = 43.5 × (supply voltage – 10.5); minimum 250 Ω for HART communication |
| Housing and Display | Aluminum with polyurethane coating, 1/2-14 NPT conduit entry; LCD display (option M5) |
| Environmental Limits | Ambient -40 to +85 °C (upper limit reduces to +80 °C with the LCD fitted); process -40 to +149 °C with traditional flange and silicone fill; storage -46 to +110 °C; 0-100% RH |
| Certifications and Safety | FM explosion-proof and dust ignition-proof (option E5); SIL 2/3 capable to IEC 61508; EMC to EN 61326 and NAMUR NE-21 |
| Physical | Approx. 5.0 × 4.3 × 7.9 in (127 × 110 × 202 mm) for the traditional flange configuration; approx. 4.0 kg (base 3051C 2.7 kg, +1.1 kg H2 flange, +0.2 kg LCD) |
| Response and Dynamics | Turn-on time under 2.0 s; damping user-selectable 0 to 36 s for one time constant; volumetric displacement under 0.005 in³ |
