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B:28
General measurement functions
B
The effect of a logarithmic Y-scale is illustrated to the
right, using a downloaded vibration spectrum.
The amplitude scale of a spectrum is automatically
scaled to accommodate the largest spectrum line (1).
Thus, a dominant line will make most others invisible,
which is desirable, because the lines containing very
little energy are insignificant for the evaluation of ma-
chine condition. In this example, the amplitude scale
is approx. 6 mm/s, so even the largest spectrum line
is fairly small.
Switching to a logarithmic scale amplifies the low am-
plitude values (2). The amplitude unit gets the addition
‘LOG’ (3). This display form clearly shows that the FFT
calculation produces spectrum lines in almost every
position, most with amplitudes well below 0.002 mm/s.
The two lower screen shots show the same spectrum
with the Y scale in dB; (4) is scaled according to Euro-
pean standard and (5) according to US Navy standard.
4
5
1
3
2
Summary of Contents for leonova emerald
Page 1: ...User guide PORTABLE EFFICIENCY ...
Page 2: ......
Page 6: ...A 2 General instrument functions A ...
Page 36: ...B 2 General measurement functions B ...
Page 74: ...C 2 Measurement techniques always included B C ...
Page 88: ...D D 2 Shock pulse measurement ...
Page 122: ...D D 36 Shock pulse measurement ...
Page 124: ...E E 2 Vibration measurement ...
Page 150: ...E E 28 Vibration measurement ...
Page 152: ...F F 2 Rotor balancing ...
Page 170: ...F F 20 Rotor balancing ...