Quadratic Calibration; Figure 34: Hydro-Com Configuration Tab - Hydronix Hydro-Probe SE User Manual

Material calibration

5 Quadratic calibration

The Hydro-Probe SE is able to utilise a quadratic calibration function for use in the rare
occasions where a material is non-linear. The equation used is show below:
Moisture % = A x (Unscaled value)² + B (Unscaled value) + C – D
Calibration Procedure
5.1
To calculate the quadratic calibration coefficients it is necessary to use analytical software,
such as Excel, to calculate the coefficients.
1. Ensure Hydro-Com is running with the calibration page open.
2. Select the correct sensor from the pull-down list in the sensor frame.
3. Start the material flowing past the sensor and start the averaging function if it is not
automatically started, then take a sample. Enough material should be collected to
obtain a representation of the material flowing past the sensor. Only take a sample
while the sensor is averaging.
4. Stop the material flow and then return to the computer, stop the averaging if it is not
automatic, and record the 'Average Unscaled' output, which should show the 'Hold'
status.
5. Mix the collected sample and determine the moisture content of the material using the
appropriate lab procedure. The sample should be split into 3 equal parts and the
appropriate laboratory test should be performed on each part.
6. If the results of the 3 samples differ by more than 0.3% moisture then one of the
samples has not been analysed correctly and the test needs to be restarted.
7. Take the average of the 3 laboratory samples
8. Record the 'Average Unscaled' value and the laboratory moisture result.
9. Repeat steps 4-9 until samples have been taken across the full working range of the
material.
10. The 'average Unscaled' and lab results should be entered into analytical software to
calculate the A, B and C coefficients plus the R² value. The coefficients should be
calculated using a second order polynomial.
11. Once the coefficients have been calculated enter the A, B and C Values into Hydro-
Com. Select the sensor on the main screen (Sensor Tab) and select the configuration
tab. The A, B and C values are entered in the Material Calibration section (Figure 34).
Once completed select 'Write' to update the sensor (Ensure that the correct sensor is
displayed at the top of the screen in red).

Figure 34: Hydro-Com Configuration Tab

Hydro-Probe SE User Guide HD0278 Rev 2.1.0 43
Chapter 5