Rockwell Automation 1441-DYN25-Z Dynamix 2500 Data Collector - Manual (Page 95)

Rockwell Automation Publication 1441-UM001B-EN-P - September 2012 95
Setting Up Measurements Chapter 3
Spectrum Measurement Definitions
The Emonitor software and the Dynamix 2500 data collector support spectrum
measurement definitions. There are unique characteristics of the Dynamix 2500
data collector that you may need to know when setting up and collecting
spectrum data:
• The Dynamix cannot collect phase with a spectrum measurement
definition.
• You can choose to have the Dynamix 2500 data collector collect a
spectrum only if a magnitude measurement at the same location is in
alarm.
Set the Collect and store condition in the Edit Storage Specification dialog
box to On Magnitude Alarm for the storage specification for the spectrum
measurement definition.
Time Synchronous Averaging in the Dynamic 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
external trigger.
• 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 Dynamix 2500 data collector data
collector, see
Number and Type of Averages on page 80 .
Order Normalized Spectra in the Dynamic 2500 Data Collector
Order normalized spectrum measurements have a frequency axis based on
multiples of the running speed (orders). This quickly identifies the frequency
relationship between each measured vibration amplitude and the running speed
of the machine. It is particularly useful on variable speed machinery.
An order normalized spectrum measurement requires a trigger input to the
Dynamix 2500 data collector.
IMPORTANT Do not check the Also collect phase data checkbox in the
Collection Specification dialog box.