Acclima Digital True TDR-305W Soil Moisture Sensor (SDI-12)

Product Summary

The TDR-305W is a 5cm waveguide version of the Acclima TDR-310W (10cm). The shorter waveguide allows this sensor to be used in significantly higher conductivity environments. Like the 310W, the Soil Smart analysis engine is also tuned for non-mineral soils often used in Controlled Environment Agriculture (CEA), such as rockwool and coco coir, yet still performs well in traditional mineral soils. It also has a much higher amplitude waveform than the H-series sensors, which consumes more power, but makes it very effective in taking measurements in challenging soil environments. 

It is a complete integrated time domain reflectometer that combines ultra-fast waveform generating and digitizing functions with a precision 5 pico-second resolution time base and highly sophisticated waveform digitizing and analyzing firmware that provides true time domain analysis of soil-propagated waveforms.

Its form factor is designed primarily for ease-of-use in non-mineral media commonly used in vertical farming applications. A probe guide is provided to ensure that the waveguide rods are parallel when pushing them into the soil. It provides reading data through a 3-wire SDI-12 interface and is compatible with any data recorder that is compliant with SDI-12 version 1.4 and earlier.

Key Features

  • Designed for easy use with rockwool blocks and even very small grow media
  • Good sampling volume with the wide spacing of the 5cm waveguides
  • Soil Smart analysis optimized for non-mineral soil types, while still works well in mineral soils
  • Ideal for high conductivity environments
  • Incident Wave Amplitude: 2.3 V
  • 20% to 80% Incident Wave Rise Time: 300 ps
  • Waveform Digitizing Resolution: 5 ps
  • SDI-12 Interface
  • 3-element 5cm stainless steel waveguide
  • 5m or 10m 3-conductor waterproof cable (standard)
  • Waterproof epoxy-filled housing

Measurement Functions

  • Volumetric Water Content: 0% to 100%
  • Medium Permittivity: 1 to 85
  • Medium Bulk Electrical Conductivity: 0 to 9000 µS/cm
  • Medium Temperature: -40 to +55 degrees C
  • Pore Water EC (Hilhorst Model): 0 to 55000 µS/cm


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