Harmonic analysis applies a sine wave at a predefined frequency. From the collected results first second and third harmonics are extrapolated. A corrosion current and Tafel slope are then calculated from the three harmonic results.
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First Harmonic |
Second Harmonic |
Third Harmonic |
The Amplitude used for the AC signal plays an important role in obtaining the best possible results always use the highest amplitude possible a test at 30mV AC will yield better results than a test at 4mV AC.
The cell potential applied to the cell is affected by two options firstly is the option Offset test to the rest potential that biases the test around the rest potential if checked the second option allows a DC Offset to be applied (with respect to RE). An example of both options a cell has a rest potential of 133mV if Offset test to the rest potential is checked and there is a DC Offset of 200mV to be applied then the test would be done at 333mV.
Advanced Settings
Each instrument undergoes a very extensive calibration procedure over a series of 8 decades of cell load 10 amplitudes and the full range of frequencies to produce a calibration matrix we call the P.A.I.R. table (Phase and Impedance Reduction). This is then applied to the raw data to reduce cable and instrument induced errors. The PAIR option is on by default it can be accessed on the Advanced options page.
