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precisive tfs tunable filter spectrometer
Optical Gas Analyzer, Tunable Filter Spectroscopy, Natural Gas Calorific Value, Wobbe Index


  • Measurement Technique
    Tunable Filter Spectroscopy
  • Measurement Ranges
    Methane: 50-100% (C1)
    Ethane: 0-20% (C2)
    Propane: 0-10% (C3)
    C4+: 0-10% (C4+ lumped)
    Carbon Dioxide: 0-20% (CO2)
    Calculated Balance: N2 (assumed for CV, WI, Density, and Specific Gravity calculations)
    Higher Heating Value (HHV)**: Per ISO 6976:2016
    Lower Heating Value (LHV)**: Per ISO 6976:2016
    Wobbe Index (WI)**: Per ISO 6976:2016
    Density: Per ISO 6976:2016
    Specific Gravity (SG): Per ISO 6976:2016
    (** Combustion reference / metering reference temperatures: 25°C / 0°C)
  • Repeatability
    Hydrocarbon Channels: ±0.05 mol% (absolute)
    CO2: ±0.05 mol% (absolute)
    HHV/LHV and WI Computation: ±0.2% (relative of reading) or ±0.1 MJ/m3 (greater of)
    Specific Gravity: ±0.05% (relative of reading)
  • Linearity Error
    <0.2% (relative of reading) or 0.1% (absolute), whichever is greater
  • Zero Drift
    Not to exceed 0.2% per month
    Maximum of 0.5% throughout life of bulb (~18 months)
  • Sample Pressure
    0.1 - 5 psig
  • Flow Rate
    0.1 - 2 L/min
  • Certifications
    CSA Class 1Div2, Groups A/B/C/D,T4. ATEx Zone 2, Ex nAnCIICT4Gc, IECEx


Precisive TFS™ Light Absorption Spectroscopy Schematic

Simplified schematic of light absorption spectroscopy

The Precisive TFS™ (Tunable Filter Spectrometer) sensor platform consists of a light source, a sample cell (for gases, liquids or solids), a wavelength separating element (spectrometer) and a photo-detector. The wavelength separating element "slices" the wavelength components of the broadband light source which then interacts with the sample molecules. Some of the wavelength components are absorbed and some are transmitted through without any absorption.

Advanced Spectral Decomposition Algorithm

Light absorption spectroscopy with advanced spectral decomposition algorithm

Precisive TFS™ Tunable Filter Spectrometers use an advanced spectral decomposition algorithm. The resulting spectrum is called absorption spectrum, which acts as "fingerprints" which are used to identify the sample components and/or quantify the composition of the sample.

Precisive® 5-282 Benefits

  • Analysis in seconds: Real-time, continuous measurement with fast response engine and turbine control.
  • No carrier gas or fuel gas requirements: Low operational costs and infrastructure requirements make it suitable for small-scale plants and terminals, and ideal for remote installations.
  • Robust calibration: Reduced maintenance and operational costs.
  • Flow-through sensor design: Minimized potential sampling and phase change issues.
  • Compact, outdoor rated, low power: Well suited for transportable spot check applications. NEMA4X/IP66 enclosure can be engine or manifold mounted. Engineered to withstand vibration and shock.

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