SKF Microlog GX Series - How to Set up HFD Measurements

Non ROUTE
How to Set Up HFD Measurements
Time Synchronous – Averaging in the time domain. This method of averaging
requires a reference trigger. Components within the signal that are
synchronous with the reference trigger are reinforced, while noise quickly
averages out. Synchronous time domain averaging produces the most
improvement in signal to noise ratio, and is advantageous whenever it is
deemed necessary to extract very low amplitude signals, or to minimize the
“noise” produced by the vibration of other machines nearby. When this
averaging method is selected, the spectrum displayed is the FFT of the
averaged synchronous time domain samples.
Peak Hold – Peak Hold holds the highest value received at each spectral line
during the averaging time. This method of averaging is very useful when the
signal contains a great deal of amplitude variation and the primary objective of
the analysis is to see the maximum reached by each component.
 For time waveforms, Average Type:Average and Average
Type:Pk Hold are not recommended. Use Average Type:Time
Sync instead.
Ext. trig. slope – Select plus or minus to determine whether the trigger occurs on a
rising or descending signal.
[+] – triggers on an ascending signal.
[–] – triggers on a descending signal.
Trigger Level – Enter a trigger level value in the text field and press an Enter button.
 If the Configuration screen Trigger Level setting is set to
Automatic, the Trigger Level setting reads “Automatic” and
cannot be set.
Bin Zeroing – Works in conjunction with the High Pass Filter setting. Choose from:
On – Zeroes everything out below the High Pass Filter setting in the FFT.
 It is recommended that you set Bin Zeroing to On, in order to
comply with the CMVA65 Microlog’s Low Frequency Cut-off
parameter.
Off – The device does not zero out all recorded FFT values beneath the
selected High Pass Filter value.
How to Set Up HFD Measurements
The GX Series Microlog supports dHFD measurements (d High Frequency Detection).
dHFD is an emulation of HFD measurements supported by the CMVA65 Microlog. Note
that, because of differences between the CMVA and CMXA platforms, not all signals will
produce identical HFD (CMVA) and dHFD (GX) readings.
 ROUTE dHFD POINTs – When collecting ROUTE data on the
Microlog, any HFD POINTs downloaded from @ptitude Analyst
software are automatically converted to dHFD POINTs (either
RMS or Peak detection).
SKF Microlog - GX Series A - 15
User Manual