EMS-81 Sap Flow Meter

EMS 81 is the most recent version of sap flow system based on a tissue heat balance (THB) method. Since 1973 when it was established, the instrumentation was seriously upgraded and theoretical background was developed and verified. The biggest advantage of this approach is direct heating of relatively large volume of xylem which brings high accuracy of the sap flow estimation. The measuring unit is quite sophisticated and therefore also expensive but the underlying theory is clear, without any uncertain empirical parameters (Tatarinov et al. 2005) and without any need for field calibration. Latest system EMS 81 enables connection of the sensor for continuous measurement of stem increment. This additional device synergistically increases the value of measured data (i.e. indirect estimation of the stem water potential, calculation of water use efficiency). Measuring system consists of the MicroSet 8X controlling unit, sap flow sensor SF 81, set of stainless electrodes, weather shields and connecting cables.

Technical Details:

  •  Channels 
    12 (for small stems or shoots)
  •  Sensor diameters 
    8-12 mm and 12-18 mm (?2 mm allowed)
  •  Heating technique 
    external soft and flexible heater
  •  Output variable 
    sap flow in [kg/hr]
  •  Temperature sensors 
    Special Thermocouple
  •  Temperature difference 
    4?C, controlled
  •  Resistance of heaters 
    100 Ohm
  •  Heating current 
    maximum 0.125 A per channel
  •  Heating power 
    maximum 1.6 W variable according to sap flow magnitude

Built-in datalogger Details:

  •  Accuracy 
    0.3% of the full scale
  •  Memory capacity 
    512 KB
  •  Memory capacity 
    220,000 values (> three months of measurement)
  •  Measuring interval 
    10 sec to 2 minutes
  •  Storage interval 
    10 sec to 1 hour

Other Details:

  •  Energy supply 
    12 V D.C. lead acid battery or DC power adapter
  •  Current consumption 
    max 2.2 A (Generally, the power consumption is proportional to sap flow rate and the number of channels in use. Daily average of 0.2 to 0.5 A is supposed.)
  •  Working temperature 
    -10 to 40 ?C
  •  Weight 
    8 kg box, 12 kg cables, 2 kg sensors and accessories
  •  Box size 
    43 x 33 x 20 cm

Scroll to Top

Please fill our short form and one of our team members will contact you back.