Application Scenarios
In a chemical plant’s tank farm, a Rosemount 2051C transmitter monitoring pipeline gage pressure begins to exhibit erratic 4–20 mA output despite a stable process. The maintenance team traces the fault to the transmitter’s electronic head—the 2051CG4A02A1AH2B2M5D4 assembly—rather than the sensor capsule or wiring. Replacing the entire transmitter would require depressurizing the line, breaking the process seal, and recalibrating the new unit from scratch. Replacing only the electronic head module allows the technician to preserve the existing manifold and impulse piping, restore signal integrity within a single shift, and perform a simple zero trim using the on-board buttons rather than a handheld communicator. For facilities managing dozens of pressure measurement points, this modular replacement path directly reduces downtime and spare-parts cost .
Parameter
| Main Parameters | Value/Description |
|---|---|
| Order Code | 2051CG4A02A1AH2B2M5D4 |
| Manufacturer | Rosemount / Emerson |
| Product Category | Coplanar Gage Pressure Transmitter (Electronic Head Assembly) |
| Transmitter Family | Rosemount 2051C Coplanar |
| Measurement Type | Gage Pressure (G) |
| Output Signal | 4–20 mA with HART digital signal (A) |
| Process Wetted Material | 316L Stainless Steel (A1) |
| Fill Fluid | Silicone Oil |
| Housing Material | Aluminum, 1/2–14 NPT conduit entry (A) |
| Display | LCD display with 0–100% scale (M5) |
| Local Adjustment | External zero and span configuration buttons (D4) |
| Mounting Bracket | Coplanar mounting bracket (B2) |
Key Parameter Notes: The M5 display option provides a two-line, five-digit LCD for direct reading of pressure, flow, or level variables, and supports local diagnostics. The D4 option adds physical buttons on the housing that allow zero and span calibration without opening the cover or connecting a communicator, a practical advantage in hazardous-area or hard-to-reach installations .
Technical Principles and Innovative Values
- Innovation Point 1: Modular Electronic Head Architecture. The 2051CG4A02A1AH2B2M5D4 is designed as a field-replaceable electronic assembly that mates to the sensor module via a sealed electrical connector. This separates the transmitter’s “intelligence” from its “sensing” function, allowing electronics upgrades or replacements without disturbing the process connection. In practice, this means a failed HART communication board or LCD does not condemn an otherwise healthy sensor capsule.
- Innovation Point 2: Coplanar Platform Integration. The 2051C Coplanar design integrates the pressure sensor, flange, and optional manifold mounting into a single compact body. Compared to traditional flange-mount transmitters, this reduces potential leak paths and simplifies installation on impulse lines or direct-mount manifolds. The 2051CG4A02A1AH2B2M5D4 configuration with 316L stainless steel wetted parts and silicone fill is suitable for a broad range of non-corrosive and mildly corrosive process fluids .
- Innovation Point 3: Local Operator Interface Without a Communicator. The D4 external configuration buttons combined with the M5 LCD allow technicians to verify and trim the 4–20 mA output at the device. This is particularly valuable during commissioning or troubleshooting when a HART communicator is not immediately available. The buttons are magnetically or mechanically actuated through the housing, maintaining the enclosure’s environmental seal.
