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Enabling better global research outcomes in soil, plant & environmental monitoring.

SNiP-GT3 For Soil Tension

The SNiP-GT3 is a 'Sensor Node Integrated Package' for LoRaWAN or CAT-M1 communication of real-time soil tension measurements for continuous soil monitoring.

Base SNiP-GT3

The base SNiP-GT3 integrates an MFR-NODE and 1x GT3-15 Transducer to a site’s unique network, communication and power requirements. The MFR-NODE can support a total of 2x GT3-15 Transducers to monitor soil tension at multiple depths.

The GT3-15 Transducer couples with a preferred Jet Fill Tensiometer (see available lengths here). The Jet Fill Tensiometer measures the force with which water is held in the soil by the soil particles.

 

See Further Specifications on the MFR-NODE
See Further Specifications on the GT3-15 Transducer
See Further Specifications on the Jet Fill Tensiometer

Measuring Principle

The soil water tension is transmitted via the ceramic cup into the tensiometer. The vacuum inside the tensiometer is measured by a pressure transducer, which gives a continuous analogue output signal.

Resolution and Accuracy

A resolution of 0.1 kPa (1 cm H2O) can be attained for the GT3 Tensiometer Transducer.
The accuracy actually obtained is related to the calibration and resolution of the AD converter. In field applications the values obtained should consider the shaft/cup length of the tensiometer: 1 cm = 0.1 kPa.

Transducer GT3-15 connection


Red: +10 V power supply

Yellow: Signal output “+”
Pressure change from 0 to -100 kPa
Output from 0 to -100 mV

Black: Battery ground

Blue: Signal output “-”
Do not connect signal output “-” to battery ground

MFR-NODE

The Multifunction Research Node has been designed to provide flexible communication, sensor and power options.

The MFR-NODE supports SDI-12 and 4 x dry contact digital inputs as well as optionally 2x differential / 4x single ended analogue inputs. The MFR-NODE supports sensors with higher power requirements; a solar panel can charge either the internal lithium-ion battery or both the node and sensor can be powered by an external 12V system (e.g. battery or mains source). Optional CAT-M1 provide an option for remote installation and in areas outside the range existing LoRaWAN networks. The optional multiconstellation GNSS ensures you won’t lose track of your device. The MFR-NODE has an onboard 8GB SD Card to provide data logging capabilities and full data redundancy in the event of temporary loss of communications or dropped packets – ideal for research applications.

  • LoRaWAN™ low-power long-range connectivity
  • 8GB SD Card for data storage
  • Supporting SDI-12, 2 x 32-bit dry-contact counting digital inputs.
  • Optional 24-bit ADC for 2x differential / 4x single ended sensor.
  • Optional CAT-M1
  • Solar rechargeable Lithium-ion or external 12V power options
  • Optional Multi-constellation GNSS
  • External solar/battery input: 12-32V DC.

 

GT3-15 Transducer

The vacuum inside the tensiometer is measured by a pressure transducer, which gives a continuous analogue output signal. A resolution of 0.1 kPa (1 cm H2O) can be attained for the GT3 Tensiometer Transducer.

GT3-15 Tensiometer Transducer -100 kPa to 100 kPa Features

  • Pressure and suction measurements (+100kPa to -100kPa)
  • Rapid response
  • Temperature compensated in the range 0–50°C — typical shift 0.5% full scale.
Range: +100kPa to -100kPa
Signal: At input 10.0 V output signal is: 0 kPa = 0 +/- 3 mV and -100 kPa = -100 +/- 3 mV
Temperature shift: Temperature compensated in the range 0–50°C—typical shift 0.5% full scale.
Voltage output: Transducer has a 4 wire output signal.
Resolution: 0.1 kPa
Accuracy: ±1.0% span

Power Requirements

Power Supply: 10.0 V DC typical, 16.0 V maximum stabilised
Current consumption: 1.3 mA @ 10.0 V