Allen-Bradley 1440-SDM02-01RA, Руководство пользователя, Страница: 78 / 168

78 Rockwell Automation Publication 1440-UM001D-EN-P - September 2016
Chapter 2 Configure the XM-124 Standard Dynamic Measurement Module
Tracking Filter Options
The Tracking Filter options apply to the Tracking Filter measurement mode
and affect the Tracking Filter measurement.
Window type Choose the type of window to be applied to the waveform measurement
before computing the spectrum:
• Rectangular - Also known as Uniform (no window). Use rectangular
only for transient signals that die out before the end of the time
sample, or for exactly periodic signals within the time sample. Gives
poor peak amplitude accuracy, good peak frequency accuracy.
• Hamming - A general-purpose window that is similar to a Hanning
window. It provides better frequency resolution but decreased
amplitude accuracy when compared to the Hanning window. Use it to
separate close frequency components. Gives fair peak amplitude
accuracy, fair peak frequency accuracy.
• Hanning - A general-purpose window that is similar to a Hamming
window. It is used on random type data when frequency resolution is
more important than amplitude accuracy. Most often used in
predictive maintenance. Gives fair peak amplitude accuracy, fair peak
frequency accuracy.
• Flat Top - Also called Sinusoidal window. Use flat top when amplitude
accuracy is more important than frequency resolution. A Flat Top
window can smear the peaks together into one wide peak, in data
with closely spaced peaks. Gives good peak amplitude accuracy, poor
peak frequency accuracy for data with discrete frequency
components.
• Kaiser Bessel - Gives fair peak amplitude accuracy, fair peak frequency
accuracy.
Number of averages Enter the number of individual data sets to be incorporated into the
averaged gSE spectrum. Averaging reduces the random errors and provides a more
reliable measurement.
Table 12 - gSE Measurement Parameters (Continued)
In this field Values are Comments
In this field Values are Comments
Tracked multiple 0.1…20 times the measured machine speed Sets the multiple of the machine speed to be tracked.
Constant Bandwidth Enter the filter bandwidth in the range of 0.1…25 Hz Select Constant Bandwidth to configure the tracking filter to
maintain a constant bandwidth as the machine speed varies.
Constant Q Enter the filter Q factor in the range of 1…200. Select Constant Q to configure the tracking filter to maintain a
constant ratio between the bandwidth and the center
frequency (machine speed).