SPM leonova emerald, Руководство пользователя

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B:30
General measurement functions
B
The previous page illustrated the three basic alternatives on the ‘Settings’ menu with single line symp-
toms. Below are examples of multi-line symptoms.
D. Same as B, but containing the first harmonic at BPFI plus
three harmonics, altogether four possible matches (5). In
this example, the match found by Leonova agrees with the
obvious peaks in the spectrum: all dashed lines are on top
of the largest lines (5).
E. Same as C, marking the positions where BPFI and its three
harmonics should be according to the calculations. In case
of the first line (6), reality as reproduced by the FFT agrees
with the calculation. However, the next three lines in the
pattern are not quite in their calculated positions: they are
beside the dashed lines (7).
Please note that such near misses are normal, especially for
the more rigid ‘Theoretical symptom’. Vibration itself is a con-
tinuous event, which is first digitalized during measurement
and the subjected to mathematical manipulations to get the
spectrum. At every step, there are tolerances, so an offset
must be expected.
The resolution of this spectrum is ≈ 1 Hz, so the line is offset
by a single digital step.
D
5
E
7
6