Rockwell Automation 1440-SDM02-01RA XM-124 Standard Dynamic Measurement Module - Manuel (Page 74)

74 Rockwell Automation Publication 1440-UM001C-EN-P - May 2014
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
prior to computing the spectrum:
• Rectangular - Also known as Uniform (no window). Use this 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 this when amplitude
accuracy is more important than frequency resolution. In data with
closely spaced peaks, a Flat Top window may smear the peaks
together into one wide peak. 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.
In this field Values are Comments
Tracked multiple 0.1 to 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 to 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 to 200. Select Constant Q to configure the tracking filter to maintain a
constant ratio between the bandwidth and the center
frequency (machine speed).