Theta Probe ML2x

• Product of

  Delta-T Devices

  Reliable and accurate measurements of soil moisture may be made simply using the ThetaProbe ML2x soil moisture sensor. It measures the percent by volume of water in the soil using the Frequency Domain method. For this purpose the changes of dielectricity constants are measured and converted to a signal tension which is proportionate to the soil moisture content. The sensor is able to measure the volumetric moisture content within a measurementrange of 5 - 55 percent by volume with an accuracy of 5% with standard calibration and with only 2 % with soil specific calibration. The output signal of the Theta Probe ML2x is 0 to 1 Vdirect current. The sensor itself consists of acylindrical plastic housing (diameter40 mm) with 4 stainless steel probes which may be simply pressed into the soil. Due to the tough and dense plastic housing with the class of protection IP 68, the Theta Probe ML2x is very wel lsuited for long term use and maybe buried completely. For this purpose the shaft of the sensorcan be extended with screw-on tubes so as to be able to install the Theta probe more easily in agreater depth. The low current consumption can be covered with5 to 15 V DC at 20 mA. The outputsignal is 0 to 1 V in direct current. The Theta Probe ML2x is supplied as standard with a 5 m long cableand a plug for connection to the output device “Moisture Meter HH2” or with open cable ends for connection to a data logger. On customer request the cable length can be extended to 100 m.

• Advantages

  • Soil specific calibration
  • Low power consumption
  • Very tough

• Technical data

  • Measurement range for water content:	0 ... 100 % volumetric water content
  • Measurement accuracy of water content:	± 0.01 m3 m-3 (1 %)
  • Conductivity range::	50 … 400 mSm-1
  • Working temperature range:	1 ... +80 °C
  • Measurement volume:	1500 ml
  • Max. cable length:	100 m