Multichannel Systems nanoZ manual - Manual (Page 22)

nanoZ User Manual
18
Impedance
spectroscopy
mode
This mode cycles through all (or a subset) of electrodes on the selected probe,
measuring the impedance of each electrode at multiple test frequencies.
(A) Select the impedance Test Frequencies (in Hz) from the check-box list, or
check All to test at all frequencies in the list. Click the notepad icon to edit the list
of test frequencies. Valid frequencies are between 1Hz and 4986Hz. The nanoZ
will generate sinusoidal test waveforms as close as possible to the specified test
frequencies. The exact test frequencies used will be displayed in the status bar
and in the column titles of the Probe report.
(B) Choose the number of Test cycles. The default setting of 40 cycles is a good
trade-off between accuracy and speed. Increasing the number of cycles will
marginally improve the accuracy due to averaging, at the expense of a longer
testing duration, whereas decreasing the number of cycles may lower accuracy
due to insufficient localization of the test signal in the frequency domain. The total
testing time per site is displayed in the status bar.
(C) The Pause setting specifies a delay, in millisconds, after switching channels
before impedance testing is begun on the currently selected electrode. In most
cases this delay can be set to zero, however with some high capacitance
electrodes the test signal may take some time to settle to baseline after switching
channels. Increase the pause setting if the ʻtest signal clippedʼ warning is
reported or some channels are not measured (i.e. skipped measurements are
blank and highlighted in yellow in the Report window).
(D) Click the Test probe button to begin the test.
Clicking on Test probe again or pressing ESC at any time will pause the test,
and you will be given the option of continuing the test or stopping. The
A B
D
C