Ex~i Flow Measurement’s flagship product, the SFC3000 flow computer, is the evolution of 45-years’ work, creating what Ex~I Flow Measurement believes is the best Gas and Liquid flow measurement computer available – backed with the best technical support.
The first generation SFC3000 was released in 2007, but before that, members of the same design team were also involved with several other predecessors of flow computer models, which in one way or another, form part of its extended family history.
Hardware and software have evolved a great deal over the decades, a quick example of this being the computational time per calculation, which has dropped from 10 seconds, down to just 100ms!
In this article, we look back through time to see how far measurement and data processing technology has evolved to lay the foundations of the SFC3000 Flow Computer.
Evolution of Gas and Liquid Flow Measurement Technology: Performance Milestones from 1980 to 2009
Gas and Liquid flow measurement instruments have evolved significantly over the past three decades, driven by advances in sensor technology, digital processing, and system integration. This application note outlines key technology milestones between 1980 and 2009, highlighting how improvements in accuracy, response time, processing capability, memory, connectivity, and user interfaces have enhanced the performance and reliability of modern Gas and Liquid flow meters and mass flow controllers.
1. Introduction
Accurate and stable Gas and Liquid flow measurement is critical in applications ranging from semiconductor manufacturing and industrial process control to laboratory research and Gas and Liquid distribution. Early Gas and Liquid flow instruments relied heavily on mechanical and analogue techniques, limiting accuracy, repeatability, and integration capability.
Beginning in the early 1980s, digital electronics increasingly enabled advanced compensation, calibration, and communication features. By 2009, Gas and Liquid flow instruments had become software-defined, networked devices with high precision, fast dynamic response, and extensive diagnostic capability.
2. Technology Milestones
2.1 1980: Predominantly Analog Gas and Liquid Flow Instruments
Measurement Performance
- Flow sensing based on mechanical elements or early thermal sensors
- Typical accuracy: ±2–5% of reading
- Limited temperature and pressure compensation
Signal Processing
- Analog signal conditioning
- Slow response times, unsuitable for fast control loops
Electronics and Memory
- Minimal microprocessor usage
- Calibration adjustments performed mechanically
- No digital storage of calibration data
Interfaces and Displays
- Analog outputs (4–20 mA, 0–10 V)
- Analog gauges or basic LED numeric displays
Application Impact
- Suitable for indication and basic monitoring
- Limited repeatability and automation capability
2.2 1982: Introduction of Digital Compensation
Measurement Performance
- Early digital linearization of thermal sensors
- Accuracy improved to ±1–3%
- Basic temperature compensation implemented
Signal Processing
- Digital averaging reduces noise
- Improved response time for control applications
Electronics and Memory
- 8-bit microcontrollers at 5–8 MHz
- EPROM-based storage of calibration curves
Interfaces and Displays
- Continued analogue outputs
- RS-232 introduced on select laboratory instruments
- Character LCDs display flow and setpoint
Application Impact
- Improved repeatability
- Early adoption in laboratory mass flow controllers
2.3 1993: Digitally Calibrated Gas and Liquid Flow Measurement
Measurement Performance
- Multi-point digital calibration
- Accuracy of ±1% or better achievable
- Gas and Liquid-specific correction factors supported
Signal Processing
- Sampling rates in the kHz range
- Digital filtering improves stability
Electronics and Memory
- 16-bit and early 32-bit processors at 20–40 MHz
- Flash memory enables field updates and multiple Gas and Liquid profiles
Interfaces and Displays
- RS-485 and early CAN bus
- Graphical LCDs with bar graphs and trends
Application Impact
- Reliable closed-loop flow control
- Improved suitability for multi-Gas and Liquid processes
2.4 2000: Software-Defined Gas and Liquid Flow Instruments
Measurement Performance
- Typical accuracy ±0.5–1%
- Integrated pressure and temperature compensation
- Improved long-term stability and traceability
- Ability to have multiple stream measurement in single unit.
Signal Processing
- Sampling rates reaching tens of kHz
- Advanced digital control algorithms reduce settling time
Electronics and Memory
- 32-bit processors at 90 MHz
- Megabytes of memory for logging and diagnostics
Interfaces and Displays
- USB and Ethernet interfaces introduced
- Menu-driven graphical user interfaces
Application Impact
- Faster process stabilization
- Simplified system integration and calibration
2.5 2009: High-Precision, Networked Gas and Liquid Flow Solutions
Measurement Performance
- Multiple streams and multiple products in one Flow Computer
- Accuracy of ±0.1–0.5% of reading
- Advanced thermal models and multi-sensor compensation
- Electronics no longer the dominant error source
Signal Processing
- PLD - assisted processing for high-speed control
- Real-time diagnostics and drift detection
Electronics and Memory
- Processor speeds exceeding 200Mhz
- Tens to hundreds of megabytes of memory
- Automatic redundancy switch over
Interfaces and Displays
- Ethernet standard
- Web-based configuration and monitoring
- High-resolution colour LCDs and touch interfaces
- In-line proving via ball, small volume provers or master meter
Application Impact
- Predictive maintenance and remote diagnostics
- Seamless integration into automated and networked systems
3. Summary of Customer Benefits
The evolution of Gas and Liquid flow measurement technology has delivered measurable benefits to end users:
- Higher accuracy and repeatability
- Faster response and improved flow control
- Reduced calibration and maintenance effort
- Enhanced diagnostics and system uptime
- Easier integration into modern control architectures
4.Conclusion
From 1980 to 2009, Gas and Liquid flow measurement instruments evolved from analogue, mechanically adjusted devices into digitally calibrated, networked systems with exceptional accuracy and performance. These advancements form the foundation of today’s mass flow meters and controllers, enabling precise, reliable Gas and Liquid flow measurement across demanding industrial and laboratory applications.
Thanks to the advances made over the years, the Ex~I SFC3000 is the culmination of 45 years of both hardware and software development. Designed, manufactured and supported in the United Kingdom and a logical replacement in any system still using one of its predecessors.
Ex~I understand the long-term stability, reliability and accuracy required by the measurement industry and has produced a flow computer that meets or even exceeds these expectations. Ex~i Flow Computer customers will continue to benefit from product range expansion through increased modularity.
Ex~I Flow Measurement is the current incarnation of BS Instruments (part of the Instromet group) and before that KDG, so a direct lineage can be drawn from the KDG flow computers in 1980 through to the SFC3000 of today.