12
SySTEM
COMpLIANCE
Manufactured under ISO 9001:2015
EM ISO/IEC 17050:2010 (CE Mark)
2014/30/EU and 2011/65/EU
EN61326-1:2013 and EN55022/CISPR 22
3.2 COMpONENTS
The TEROS 10 sensors use an electromagnetic field to measure the apparent dielectric
permittivity (
e
a
) of the surrounding medium. The sensor supplies a 70-MHz oscillating wave
to the sensor needles, which charge according to the dielectric of the material. The charge
time is proportional to substrate dielectric and substrate VWC. The TEROS 10 microprocessor
measures the charge time and outputs a raw value based on the substrate dielectric
permittivity. The raw value is then converted to VWC by a calibration equation specific to the
substrate (
).
Needle 1
Needle 2
Sensor
body
Ferrite
core
Figure 4 TEROS 10 sensor
A ferrite core positioned on the TEROS 10 sensor cable 7.6 cm (3 in) away from the sensor
head is utilized to isolate the sensor from any interferences in the system. This mitigates any
potential noise from the system on the measured sensor data. It is important to not attach
anything to the section of cable between the sensor head and the ferrite core as this may
influence the measurements.
