Electrical conductivity probe CS655

volumetric water contentreflectionfor soil

The CS655 is a multiparameter smart sensor that uses innovative techniques to monitor soil volumetric-water content, bulk electrical conductivity, and temperature. It outputs an SDI-12 signal that many of our dataloggers can measure. It has shorter rods than the CS650, for use in problem soils. This product is supplied with a 3 m cable as standard, other lengths available to order. Benefits and Features - Larger sample volume reduces error - Measurement corrected for effects of soil texture and electrical conductivity - Estimates soil-water content for a wide range of mineral soils - Versatile sensor—measures dielectric permittivity, bulk electrical conductivity (EC), and soil temperature The CS655 consists of two 12-cm-long stainless steel rods connected to a printed circuit board. The circuit board is encapsulated in epoxy and a shielded cable is attached to the circuit board for data logger connection. The CS655 measures propagation time, signal attenuation, and temperature. Dielectric permittivity, volumetric water content, and bulk electrical conductivity are then derived from these raw values. Measured signal attenuation is used to correct for the loss effect on reflection detection and thus propagation time measurement. This loss-effect correction allows accurate water content measurements in soils with bulk EC ≤8 dS m-1 without performing a soil-specific calibration. Soil bulk electrical conductivity is also calculated from the attenuation measurement. A thermistor in thermal contact with a probe rod near the epoxy surface measures temperature.