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Which Sap Flow Meter Do I Need?

Since 2006, ICT International has undertaken a continuous improvement strategy to produce a comprehensive range of sap flow sensors, meters, instruments, and devices. Using the Heat Ratio Method (for the SFM1 and SFM1x) and Heat Field Deformation (for the HFD Sap Flux Meter), these have taken proven scientific methods to become the leading plant water use measurement solutions.

The Heat Ratio Method is explained in the Sap Flow Measurement article, whilst the Heat Field Deformation method is explained on the HFD Sap Flux Meter page.

HFD Needles

Sensor, meter, instrument, or device?

At the core of the sap flow measurement solutions is the definition of whether it is a sensor, meter, instrument, or device.

  • Sensor: converts a physical property into an electrical signal that can be directly related (using first principles) to a biophysical activity.
  • Meter: the reading of the sensor output, and subsequent conversion into a meaningful output for later analysis. Able to perform calculations from the raw measurements for subsequent analysis of derived values.
  • Instrument: a combination of the sensor and meter, often with internal data storage. Contains power (battery) and power supply control (charging circuit).
  • Device: an instrument with internet connectivity (either through LoRaWAN or Cellular) that can transmit the collected data to a cloud-based platform (such as the Eratos SFM Water Usage Workflow, Eagle.io, or Whysor). Importantly, the ICT International range of IoT Devices are platform agnostic, so can be integrated into any existing platform solutions, for example Microsoft Azure as is often used by local government, or a self-managed server solution.

Importantly, a sensor will always require connection to a meter or a data logger to allow collection of the data.