Analysis of the Sensor Architecture and Signal Processing Chain for Gas Mass Flow Meters

2025-11-13

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The sensor architecture of the gas mass flowmeter is the key to achieving highly accurate measurements.

ACU10FA-LM Analog Gas Mass Flow Meter, ACU10FD-MM Digital Gas Mass Flow Meter

 

Commonly used thermal gas mass flow meter sensors typically consist of two reference-grade resistance temperature detectors (RTDs): a velocity sensor and a temperature sensor. The velocity sensor is heated to a temperature higher than that of the medium, while the temperature sensor measures the actual temperature of the medium itself. When gas flows past the sensor, it carries away heat, causing the velocity sensor's temperature to drop. To maintain a constant temperature difference, the heating power must be adjusted—this adjustment is closely related to the gas mass flow rate.

Working Principle Diagram

The signal processing chain is responsible for converting the weak electrical signals output by the sensor into readable flow data. The sensor’s output signal first passes through an amplifier to boost its strength, enhancing the overall signal intensity. Next, the signal undergoes filtering to eliminate noise interference, ensuring signal purity. Finally, the processed signal enters the signal processing unit, where it is converted from an analog signal to a digital signal via an analog-to-digital converter (ADC), making it ready for subsequent digital processing.

ACU20FD-MM High-Precision Gas Mass Flow Meter

 

During the digital processing stage, the microprocessor analyzes the digital signal according to a pre-set algorithm, calculating the mass flow rate of the gas. To enhance the accuracy and stability of the measurement, the signal-processing chain may also incorporate additional steps such as temperature compensation and linearization, which help eliminate the influence of environmental temperature, gas composition, and other factors on the measurement results. Finally, the processed flow data is transmitted via a communication interface—such as RS-485 or HART—to a host computer or control system, enabling remote monitoring and automated control.

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