Description
Foxboro X440
Technical Specifications
- Measurement Type: Differential Pressure (DP), Gauge Pressure (GP), or Absolute Pressure (AP).
- Accuracy: Up to ±0.04% of the calibrated span.
- Output Signal: 4-20 mA with HART® protocol.
- Turndown Ratio: Up to 100:1, allowing for wide-ranging applications.
Functional Features
- Advanced Diagnostics: Continuously monitors sensor health, process conditions, and electronics to predict failures before they occur.
- Dynamic Damping: Adjustable response time to filter out process noise without sacrificing control loop performance.
- Wireless Capability: Optional WirelessHART integration for easy installation in remote or hard-to-wire locations.
- Easy Calibration: Push-button or HART-based calibration eliminates the need for physical pressure sources in many cases.
Application Scenarios
Widely used in oil and gas production, refining, chemical processing, and power generation for critical measurements such as boiler drum level, custody transfer flow, and reactor pressure.
Performance Parameters
- Stability: ±0.1% of upper range limit per 5 years.
- Response Time: Adjustable from milliseconds to seconds.
- Ambient Temperature Limit: -40°C to +85°C without LCD display.
Material Composition
The wetted parts (sensor module) are typically constructed from 316L stainless steel, Hastelloy C-276, or Tantalum for corrosion resistance. The electronics housing is made of low-copper aluminum alloy or 316 stainless steel with a durable epoxy/polyurethane coating.
Structural Characteristics
Features a compact, robust design with a rotatable electronics housing for easy access. Includes a built-in LCD display for local indication and configuration. The sensor module is bolted to the housing, allowing for easy replacement without disturbing process connections.
Working Principle
The transmitter uses a capacitance or piezoresistive sensor to convert applied pressure into an electrical signal. The microprocessor linearizes, temperature-compensates, and scales this signal, then outputs a precise 4-20 mA current loop proportional to the measured variable, superimposed with digital HART data.
Installation Requirements
Mount the transmitter as close to the process as possible. Use proper impulse tubing with correct slope to prevent gas or liquid traps. Ensure the process fluid is compatible with the wetted materials. Ground the transmitter housing according to local electrical codes.
Usage Precautions
- Never exceed the maximum working pressure or temperature limits.
- Avoid water hammer or pressure spikes that can damage the sensor.
- Perform regular zero checks and calibrations to maintain accuracy.
