Frequency Response Function Module
Recording the Measurement
Windowing
– Sets the FFT window type to
Uniform
or
Force/Exponential
.
Num of Averages
– Sets the number of FFT averages.
Accept/Reject
–
When carrying out a hammer test, setting
Accept/Reject
to
Manual
displays a dual time trace and presents the user with an accept or reject control. Setting
it to
Automatic
automatically rejects overloaded data and double impacts.
Invert Phase
– Applies a 180
o
phase offset to the measured data. It is used when the
accelerometer or hammer needs to be inverted at a measurement position.
Save To
– (
Internal
or
Card
) Specify the medium to record to, either the Microlog’s
internal disk or an inserted SD card.
Posn. Autoincr
–
W
orks with modal analysis software, if this parameter is set to
On
,
then an additional
Start Index
field appears and prompts for the index’s starting
number. For example, if the
Start Index
is set to
1
, then the FRF file is saved as 0001
by default, and then the next file saved is saved as 0002, and so on.
•
After setting FRF setup fields, if desired, press the
Save
function button to name
and save the current settings for future recall.
Recording the Measurement
Once the measurement is set up and the transducers are attached correctly, the next
step is to start collecting data for the FRF.
To Collect FRF Data:
•
From the
Setup
screen, press the
Start
function button.
If you have
Hammer Range
,
Response Range
or
Num of Lines
set to automatic, a
message displays advising you that you will be asked to perform three trial hits. The
results of these hits are used to automatically determine the best settings for the
associated options.
SKF Microlog - GX Series
8 - 7
User Manual
