The CS640 is used in TDR100 and TDR200-based systems. This probe consists of a Santoprene head, three pointed rods, and a standard RG58 cable. The length of each rod is 7.5 centimetres, allowing the probe to be used in very high electrical conductivity soils or in laboratory column applications (maximum soil bulk electrical conductivity of 5 deciSiemens/metre). The RG58 cable is suitable for lengths up to 15 metres (50 ft) as measured from the tips of the probe's rods to the TDR100 reflectometer. A similar probe, the CS645, is recommended for applications requiring longer cable lengths. The CS640 and CS645 differ only in their cables.Read More
The CS640 acts as a wave guide. Impedance along the rods varies with the dielectric permittivity of the surrounding soil. Because the dielectric permittivity of soil primarily depends on the amount of water present, soil volumetric water content can be inferred from the reflected measurements. Soil bulk electrical conductivity is determined from the attenuation of the applied pulse.
A single TDR probe can be connected to a TDR200 or TDR100 reflectometer. Multiple probes can be connected to the SDM8X50 or SDMX50 coaxial multiplexer.
PCTDR version 3 software supports sensor setup and includes a CRBasic program generator for TDR200 and TDR100 programs.
|Maximum Soil Bulk Electrical Conductivity||5 dS/m|
|Rod Diameter||0.16 cm (0.063 in.)|
|Rod Length||7.5 cm (2.95 in.)|
|Santoprene Head Dimensions||4.5 x 2.2 x 1.0 cm (1.8 x 0.9 x 0.4 in.)|
Number of FAQs related to CS640-L: 1
In applications where TDR probes are used to measure soil water content, the maximum distance from the TDR probe back to the TDR100/TDR200 (even through one or more multiplexers) cannot exceed 15 m (50 ft) when using RG58 coaxial cable; the CS605-L, CS630-L, and CS640-L TDR probes have an RG58 cable. When using low-loss coaxial cable, the distance cannot exceed ≈25 m (80 ft); the CS610-L, CS635-L, and CS645-L TDR probes have a low-loss coaxial cable.
In slope stability and rock mass deformation applications, the maximum coaxial cable length should not exceed ≈1 mile (5,280 ft). The maximum combined length of all SDM cables in the system should not exceed ≈76 m (250 ft).