S421 – In-line Thermal Mass Flow Meter
Thermal Mass Flow Sensor with Pipe Section
- Individual factory calibration on the complete measuring section, ensuring high accuracy and excellent repeatability even under variable flow conditions.
- Dual calibration curve stored in internal memory, ideal for operation with two different gases or different operating ranges without the need for recalibration.
- Integrated pipe design that ensures stable and reliable measurement by eliminating errors caused by irregular flow profiles.
- Fast response to flow changes, suitable for dynamic processes and continuous monitoring.
- Robust industrial construction, designed for continuous operation in demanding industrial environments.
- Direct mass flow measurement, reducing sources of error and simplifying commissioning.
Description

Stop estimating consumption in your plant and get real, reliable flow data.
The S421 flow and consumption sensor is designed to deliver precise and stable measurement across a wide flow range. Thanks to its high resolution and fast sampling rate, it detects flow variations in real time, making it ideal for industrial applications that require continuous control.
Installation is carried out using a dedicated measuring section with R-type threaded or flanged connections, ensuring an optimal flow profile and consistent results. The sensor can store two calibration curves, enabling operation with two different gases without compromising accuracy.
Optionally, the integrated color display allows simultaneous visualization of all measured variables and simplifies device configuration—such as pipe diameter, gas type, and analog output scaling—making commissioning fast and intuitive.
Applications
Precise measurement of flow and consumption in industrial gas lines, even with two different gases, thanks to the integrated dual calibration curve.
Use in demanding industrial environments where robust and reliable equipment is required.
Easy integration into monitoring and automation systems via analog outputs, pulse signals, or Modbus RTU communication.
Consumption control and analysis in production processes, distribution networks, and energy efficiency applications.
Advantages
High accuracy and fast response, even with dynamic flow changes.
Wide measuring range, suitable for diverse process conditions.
Industrial design with IP65 protection, ideal for continuous plant operation.
Communication flexibility, enabling easy integration with PLCs, SCADA, or energy management systems.

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Designed for professional installation
The S421 has been developed to simplify both installation and long-term operation in industrial environments. Its modular architecture allows the selection of the appropriate measuring section according to pipe diameter, ensuring compatibility with different plant configurations.
The device is designed for continuous operation, with protected electronics and components optimized to minimize maintenance. In addition, its structure enables fast commissioning, reducing installation time and avoiding unnecessary process downtime.
This combination of design, reliability, and ease of use makes the S421 an ideal solution for new projects, plant expansions, or the replacement of obsolete measurement systems.

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