Rockwell Automation 441-PEN25 Enpac Ex Data Collector User Manual
Page 63
Publication GMSI00-UM001A-EN-E - February 2005
Setting Up Measurements 57
Next, find the total collection time for the time waveform measurement
using this formula.
Time synchronous averaging in the Enpac Ex
• Time synchronous averaging cancels out the effects of signals not
related to the synchronizing trigger. Time synchronous mechanical
effects include imbalance, misalignment, eccentricity of bent shafts,
blade passing, and gear meshing.
• Time synchronous averaging requires an external trigger input to the
Enpac Ex.
• Set up a collection specification with the averaging Type set to "Time
Synchronous" and enter the Number of averages. Use a large number
of averages (such as 20 or 30) to get the desired reduction in
non-synchronous effects. For more on supported averaging in the
Enpac Ex, see Number and Type of Averages on page 45.
EXAMPLE
If you had a Maximum frequency value of 7200 CPM and
a Number of lines value of 400, you would:
1. Convert CPM to Hz.
2. Find the total collection time.
WARNING
Do not connect the Enpac Ex to an external trigger unless
the area is known to be nonhazardous.
collection time
spectral lines
Fmax (Hz)
-------------------------------
=
7200 CPM
60
--------------------------
120 Hz
=
400 lines
120 Hz
---------------------
3.3 seconds
=