Figure 15: Typical Calibration Results - Hydronix Hydro-Probe Configuration And Calibration Manual

Chapter 3
A sensor material calibration correlates the Unscaled value to a 'real' moisture (Figure 15).
This correlation is determined by measuring the Unscaled value of a material at various
moisture or Brix contents and collecting a sample of the material. The moisture in the sample
is determined using an accurate laboratory process. The full recommended process is
detailed in this user guide.
Material Changes
2.3
It is important to position the sensor where there is an adequate and consistent flow of
material. Fluctuations in the composition of the material such as varying blends, density or
compaction may adversely affect the validity of the calibration. See the Installation guide for
the appropriate sensor for mounting advice.
For further advice regarding specific applications please consult the Hydronix support team
support@hydronix.com
The Calibration Types
2.4
Hydronix Microwave Moisture Sensors can be calibrated using several different methods.
Linear:
A material calibration for moisture is normally linear, and calibrating to this is described on
page 32. The following equation is used:
Moisture % = B x (Unscaled Reading) + C - SSD
Quadratic:
There is also a quadratic function for use in the rare cases when the measurement of the
material exhibits non-linear characteristics, a quadratic term can be used in the calibration
equation as shown below.
Moisture % = A x (Unscaled reading)² + B (Unscaled reading) + C – SSD
Use of the quadratic coefficient (A) would only be necessary in complex applications and for
most materials the calibration line will be linear in which case 'A' is set to zero.
Brix:
Selected sensors have the capability of being calibrated to Brix (Dissolved solids).For a Brix
calibration a different type of line is used using the equation:
=
Brix
For more information on calibrations and determining the correct calibration to use contact the
Hydronix Support Department at support@hydronix.com.
30 Configuration and Calibration Guide HD0679 Rev 1.2.0
Sensor
Unscaled
10
20
30
40

Figure 15: Typical Calibration Results

− ⋅ ⋅ + ⋅
( C us )
A B e D us ²
Sensor Integration and Material Calibration
Laboratory
Moisture Result
5
10
15
20