Rosemount 402-996-309 Differential Pressure Transmitter Assembly

Module Feature

402-996-309 is a differential pressure sensor module from Rosemount. It converts differential pressure acting on the sensing diaphragm into standard electrical signal. It supports 4-20mA or HART digital communication. It has stable anti-vibration and anti-corrosion performance, can be matched with various process isolating diaphragms and capillary assemblies. Widely stocked as spare for refinery, chemical plant and power station process measurement cabinets.

Working principle

High pressure side and low pressure side process pressure act on the sensing diaphragm. The internal capacitance or strain sensing element detects diaphragm displacement caused by pressure difference. The signal conditioning circuit converts tiny physical variation into standard 4-20mA analog signal with superimposed HART digital signal for remote reading and parameter configuration.

Onboard components

Sensing diaphragm, pressure sensing element, signal conditioning PCB, temperature compensation circuit, sealing body and electrical terminal block.

LED indicators

Front LEDs indicate power and fault alarm status.

Hardware self‑diagnosis

Module monitors internal temperature, sensor drift and circuit health. Range and damping parameters can be configured by HART communicator.

Programming software

Rosemount AMS Device Manager, used for range setup, trim calibration and fault diagnosis.

Electrical & Process Parameters

Model: 402-996-309 Brand: Rosemount Device type: Differential pressure transmitter sensing module Function: Differential pressure, flow and liquid level measurement for industrial process

Mechanical & Structure

Mounting: Direct process mounting or manifold mounting Protection class: IP66 Housing: Stainless steel / alloy pressure body

Environmental

Operating temperature: -40℃ ~ +85℃ Storage temperature: -50℃ ~ +100℃ Ambient humidity: 5~95% non‑condensing

Certification: CE, IECEx Status: Original Rosemount process instrument spare

Installation

Isolate process pressure and bleed manifold before replacement. Mount module on pressure manifold, connect high/low pressure tapping lines, wire 24V DC signal loop, perform zero calibration and range verification after commissioning.

Interface

High pressure port, low pressure port, 4-20mA / HART signal terminals.

Diagnostic

No output: 24V loop power missing or wiring open. Signal drift: Zero point shift or diaphragm damage. HART communication failure: Loop resistance insufficient or short circuit.

Product Brief

402-996-309 transmitter module, Rosemount differential pressure sensor spare for industrial flow and level process measurement replacement.