SFM1 Sap Flow Meter

The SFM1 Sap Flow Meter is a self contained, stand-alone instrument for the measurement of sap flow or transpiration in plants.

  • Product Name:SFM1 Sap Flow Meter
  • Model:SFM1
  • Maunufactor:ICT
  • Country:AU

The SFM1 Sap Flow Meter is a self contained, stand-alone instrument for the measurement of sap flow or transpiration in plants. The SFM1 is a complete package containing sap flow sensors, data logger, interface software and internal battery which can be charged with an external solar panel. The SFM1 Sap Flow Meter is a new model which replaces the HRM30 sap flow measurement sensor.

Utilising the Heat Ratio Method (HRM) principle the SFM1 Sap Flow Meter is able to measure high, low and reverse flow rates in both small woody stems & roots as well as large trees. Like the Heat Field Deformation (HFD) principle, the HRM Sap Flow Meter is the only instrument that can measure zero flow and reverse sap flow rates. The SFM1 Sap Flow Meter is the most powerful and flexible instrument for the direct measurement of plant water use.


Low & Zero Sap Flow Rates

Reverse Sap Flow Rates

Night Time Water Loss

Stem Sizes>10mm

Sap Flow in Roots

Arid Ecosystems & Drought

Radial Sap Velocity Profiles

Sap Flow of Grapevines


 Accessories include:

– SFT1 – Sap Flow Tool Software

– MCC1 – Wireless USB Radio communication device

– MCC2G – Remote Data Access Hub for Data To Web access via GSM

– SFM-SK1 – SFM Installation Kit

– SFM-55 – Pack of 10 Drill Bits

– SFM-TB – HRM block, Functional verification standard

– SP22 – 20 Watt Solar Panel and SPPM – Solar Panel Post Mount


  • Output Options

        Raw Temperatures:     °C

        Heat Pulse Velocity:     cm hr -1

        Sap Flow:     cm 3 hr -1 (Litres hr -1 )

  • Range      -100 to +100 cm hr -1

  • Resolution      0.01 cm hr -1

  • Accuracy      0.5 cm hr -1

  • Measurement Duration    120 seconds

  • Heat Pulse    

        User Adjustable:     20 Joules (default) approx. Equivalent

        to a 2.5 second heat pulse duration, auto scaling.

  • Logging Interval

        User Adjustable:     Minimum interval, 3 minutes,

        recommended minimum 10 minutes.


  • Computer Interface    USB, Wireless RF 2.4 GHz

  • Data Storage    MicroSD Card

  • Memory Capacity    Up to 16GB, 4GB MicroSD card included.


  • Needle Diameter    1.3 mm

  • Needle Length    35 mm

  • Measurement Positions    2 per measurement needle

  • Measurement Spacings    7.5 mm and 22.5 mm from the needle tip

  • Dimensions L x W X D    170 x 80 x 35 mm

  • Weight    400 g


  • Internal Battery Specifications

        960mAh Lithium Polymer, 4.20 Volts fully charged

  • External Power Requirements

        Bus Power

        8-30 Volts DC, non-polarised, current draw is 190mA

        maximum at 17 volts per logger

        USB Power    5 Volts DC

  • Internal Charge Rate

        Bus Power

        60mA – 200mA Variable internal charge rate, maximum

        charge rate of 200mA active when the external voltage

        rises above 16 Volts DC

        USB Power    100mA fixed charge rate

  • Internal Power Management

        Fully Charged Battery    4.20 Volts

        Low Power Mode    3.60 Volts – Instrument ceases to take measurements

        Discharged Battery

        2.90 Volts – Instrument automatically switches off at and

        below this voltage when no external power connected.

  • Battery Life varies

      • With a recommended power source connected, operation can be continuous.

      • Approximately 1.5 days with a heat pulse of 50 Joules and a measurement

        interval of 30 minutes – no external power present to recharge battery.