Percometer

Percometer is a reliable, accurate, lightweight and easy-to-use instrument for measurements of dielectric constant (permittivity), electrical conductivity and temperature. Permittivity is measured by the change in the electrical capacity of the electrode (probe) due to the influence of the measured material on 40-50 MHz. By means of a propriety schematic solution only a change in the capacitive current component is measured, i.e. conductivity does not influence the measurement result. Conductivity is measured by a separate channel with an alternating current 1 kHz signal and is expressed as µS cm–1

Adek Percometer v.7 has five optional measurement modes:

1. Continuous measurement of the dielectric constant value
2. Continuous measurement of the electrical conductivity value
3. Single point measurement of dielectric constant and electrical conductivity values simultaneously
4. Statistical multipoint measurement of dielectric constant and electrical conductivity values (average calculated), TST mode 
5. Automatic dielectric constant and conductivity measurements with given time interval and number of points


Temperature is measured with each measurement of the dielectric value (modes 1, 3, 4, 5).

The Percometer has two standard probe types:

1. Surface probe for measurements on the face of structures or material samples (probe’s length 170 mm, sensor diameter 60 mm)

2. Tube probe for soil and aggregate sample measurements approx. 15 cm inside the material (probe’s length 150 mm or 1000 mm, diameter 28 mm)

Each probe is calibrated individually to enable automatic self-calibration for measurements. It is possible to calibrate 24 different probes per Percometer. Measurement results can be stored in the Percometer’s central unit memory (max 1300 measurement results). Recorded measurement data can be transferred to a PC via RS232, for use e.g. in Excel. Modem connection for remote operation is possible.

The measured dielectric value is the real part of the complex relative dielectric permittivity. It can be calculated from the change of the fringe capacity of the probe, caused by the material under test. Dielectric measurements using the Percometer are reliable when the conductivity of the measured material is:

< 1000 µS cm–1 for tube probe measurements

< 2000 µS cm–1 for surface probe measurements

It is also possible to design special type of probes for different materials:

 Adek Percometers are utilized today e.g by the laboratories, geoservice and road data service units of the Finnish Road Enterprise, and in the Geotechnical Laboratory of the Tampere University of Technology. In the United States and Canada, Percometer is used, among others, by the Texas Transportation Institute, the Texas Department of Transportation, the Office of Minnesota Road Research and the University of Saskatchewan. The Percometers are also used in the soil study for soil moisture and salinity determination. 

Percometer v.7 Probes data