Rockwell Automation 1441-PEN25-Z Enpac 2500 Data Collector User Manual
Page 90
90
Rockwell Automation Publication GMSI10-UM002D-EN-E - August 2012
Chapter 2
Setting Up Measurements
Next, find the total collection time for the time waveform measurement
using this formula.
Time Synchronous Averaging in the Enpac 2500 Data Collector
•
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 the internal laser tachometer or an
external trigger input to the Enpac 2500.
•
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,
.
Typical Time Waveform Measurement Definitions
This figure shows the setup for a typical time waveform measurement definition.
Figure 18 - Time Waveform Measurement Definitions
EXAMPLE
If you had a Maximum frequency value of 7200 CPM and a Number of lines
value of 400, you would:
ATTENTION: 1. Convert CPM to Hz.
ATTENTION: 2. Find the total collection time.
collection time
spectral lines
Fmax (Hz)
-------------------------------
=
7200 CPM
60
--------------------------
120 Hz
=
400 lines
120 Hz
---------------------
3.3 seconds
=