53
<Table VI-2-1> Relationship of Maximum RPM, Sampling Frequency and Buffer Size
Max. RPM
Sampling Frequency(Hz)
Buffer Size
12000 512 1024
24000 1024 2048
48000 2048 4096
96000 4096 4096
As mentioned in V-2-4 paragraph, a frequency analysis generates a picket fence error. We can’t get
an exact frequency which corresponds to rotational RPM. As this problem, the system has a
compensation algorithm.
3. Measuring with RPM Meter
Button
changes another mode into RPM mode and, at the same time, RPM option setting
button
is activated. This mode doesn’t offer the recording except arming.
RPM Meter has the RPM window and FFT graph window as [Fig. VI-3-1]. FFT graph window has
two vertical lines for setting range of a first frequency. To calculate RPM from the maximum peak in
a defined region by two vertical lines, you have to drag lines with stylus pen.
[Fig. VI-3-1] RPM Meter
[Fig. VI-3-2] Option Setting Window
The option setting window is shown in [Fig. VI-3-2] and maximum rpm and averaging number
shall be selected. Sampling frequency is calculated from maximum RPM as <Eq. VI-3-1> equation.
.
2.56
60
s
Max RPM
F
=
×
<Eq. VI-3-1>
Cross mark ‘+’ represents the maximum value in all frequency with no correlation of vertical lines.
If you set an unfit range, you would get a fault RPM from a fault frequency.
Two vertical lines
Summary of Contents for SLA-PA201
Page 64: ...64 Appendix 1 The Theory for calculating RMS by ISO2631 and ISO8041 ...
Page 67: ...67 Appendix 2 Frequency Response of Filter in the Vibration Level Meter ...
Page 75: ...75 Appendix 3 Theory of WBCombined Filter and Frequency Response ISO6954 Filter ...
Page 79: ...79 Fig 2 Lowpass Filter with 100Hz Cutoff Fig 3 a v transition Frequency Response ...
Page 88: ...88 Fig 12 Error between theoretical value and measured value ...
