14
SYSTEM
Ferrite
core
TEROS 12
thermistor in Needle 2
TEROS 11
thermistor located on
PCB near Needle 1
Needle 3
Needle 2
Needle 1
VWC
EC
Figure 4 TEROS 11/12 sensor
A ferrite core positioned on the TEROS 11/12 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.
The TEROS 11/12 VWC measurement sensitivity is contained within a 1,010-mL volume
roughly depicted in
. Please see the application note
volumetric water content sensors
for testing protocol and more thorough analysis.
3 cm
3 cm
3 cm
1 cm
1 cm
7.5 cm
9.3 cm
3 cm
Figure 5 VWC volume of influence
NOTE: The TEROS 11/12 provides instantaneous or near-instantaneous measurements; however, because of the
sensitivity of the measurement of the sensor head, the TEROS 11/12 is not well suited for spot measurements of VWC.
