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  Updated: 10 May 2020


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Active air speed transmitters for ducts

Air speed, temperature and relative humidity.

Analog output 4…20mA or 0…10Vdc.

There are several Probe type lengths available.

The FXT transmitters are employed to control air speed in air conditioning and ventilation systems (HVAC / BEMS) in the following sectors:

  • pharmaceutical

  • museums

  • clean rooms

  • ventilation ducts,

  • industrial sectors

  • crowded places

  • cafeterias

  • auditoriums

  • gymnasiums

  • farms with large numbers of animals

  • farmaceutisk
    rena rum
    fullsatta ställen
    gårdar med ett stort antal djur









    Datasheet Datasheet



    The sensors in combination with an accurate electronics guarantee precise and reliable measurements over time.

    The sensor for air speed is a thin film, the probe sheath is AISI304, the filter for relative humidity of 20μ wire mesh, materials that can be used in hostile areas.

    There are two possible installations: in the FXT version, the horizontal probe is joined to the electronics enclosure while in the FZT version the probe is conconnected to the electronics through a cable.

    In the FXT version, the duct probe is fixed to the electronics enclosure and it is available in three different lengths.

    To fix the probe to the duct, you can use, for example, the MFC flange, a 3/8” universal biconical connection or a PG16 metal cable gland (14mm).

    In the FZT version, the probe together with the sensors is equipped with a cable which can be 2.5 or 10 meters long.

    The probes are available in three different lengths and several different models.

    • Airspeed measurement with the FXT  serie analog output 4-20mA or 0-10Vdc

    • Airspeed and Temperature measurement with the FTT serie – analog outputs 4-20mA or 0-10Vdc

    • Airspeed, Humidity and Temperature measurement with the FTH-serie serie – analog outputs 4-20mA or 0-10Vdc


    High Precision Air/ Gas Velocity Transmitter
    The air velocity transmitters were developed to obtain accurate measuring results over a wide range of velocities and

    A high-quality hot film sensor element based on cutting- edge thin film technology ensures maximum sensitivity, even at lowest mass flows.

    At the same time, the innovative probe design produces reliable measuring results at high flow velocities of up to 40m/s.

    The integrated temperature compensation minimises the temperature cross-sensitivity of the transmitter series which, combined with the
    robust mechanical design, allows it to be used at process temperatures between -40 to

    In addition to air velocity and temperature values, the transmitter calculates the volumetric flow rate in m³/h or ft³/min.

    The cross section of the duct needs to be determined for this purpose and the volumetric flow rate can be displayed and directed to one of the analogue outputs.

    The transmitters can be used to measure the velocity of other gases as well, although a correction has to be applied to the unit at the

    Technical data

    • Measuring range:

      • 0...2m/s

      • 0...10m/s

      • 0...40m/s

    • -40...120°C

    • Response time: < 1.5s...40s (can be configured)

    • Outputs: freely scaleable in the ranges of

      • 0...10V and

      • 0...20mA (e.g. 4...20mA)

    • Accuracy:

      • +/-0.05m/s

      • +/-0.1m/s

      • +/-0.2m/s

      • +/-0.5°C

    • Supply: 24Vac/dc

    • Operating range: 0...40m/s (0...8000ft/min)
      -40...120°C (-40...248°F)

    • Pressure-tight models up to max. 10bar


    Model A


    Model  B


    Model C


    Model E






    E-mail: lars@fjellcom.se     

    Phone: +46(0)31-287202

    Mobile: +46(0)706-755561



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