Rockwell Automation 1440-VSE02-01RA XM-122 gSE Vibration Module - Manual (Page 73)

Publication GMSI10-UM013D-EN-P - May 2010
Configuration Parameters 63
Measurement Parameters Overall Measurement Parameters
There are two instances of the overall measurement parameters, one for each
channel. Use these parameters to configure the measurement type and the
filtering performed for each overall measurement.
Overall Measurement Parameters
Parameter Name Description Values/Comments
Signal Detection The measurement (or calculation) performed on the
input signal to produce the Overall Value. See Data
Parameters on page 89.
•
RMS - The Overall Value is the root mean squared
(RMS) signal level of the input signal.
•
Calculated Peak - The Overall Value is the
measured RMS value multiplied by the square root
of two (1.4142).
•
Calculated Peak-to-Peak - The Overall Value is
the measured RMS value multiplied by two times
the square root of two (2.8284).
•
True Peak - The Overall Value is the output of a
peak detector applied to the input signal.
•
True Peak-to-Peak - The Overall Value is the
output of a peak-to-peak detector applied to the
input signal.
Options: RMS
Calculated Peak
Calculated Peak-to-Peak
True Peak
True Peak-to-Peak
Important: When changing the signal
detection, make certain to check the
Overall Time Constant value.
Overall Time Constant For RMS measurements, the Overall Time Constant
parameter sets the 3-DB bandwidth for the digital
filtering used to calculate the Overall Value. The
3-dB bandwidth is roughly equal to 1 / (2
π
x Overall
Time Constant). The greater the Overall Time
Constant, the slower the response of the measured
Overall Value to change in the input signal.
For example, an Overall Time Constant of 0.1
seconds may be appropriate for monitoring the
Overall Value of an input signal with a fundamental
frequency of 10 Hz and above. Although, the
response to a step change in input will take
approximately 2.2 times the Overall Time Constant to
settle. Therefore, for an Overall Time Constant of 0.1
seconds, the settling time will be approximately 0.22
seconds.
For True Peak measurements, the Overall Time
Constant sets the decay rate of the peak detection
meter. The greater the Overall Time Constant, the
slower the Peak is decayed.
Enter a value greater than 0 (zero).
Recommended Value:
The recommended values are
appropriate for a typical 50/60 Hz
machine, and may need to be adjusted
depending on the application.
•
For True Peak or True
Peak-to-Peak measurements, set
the Overall Time Constant to 1.5.
•
For RMS, Calculated Peak, or
Calculated Peak-to-Peak
measurements, set the Overall Time
Constant to one of the
following:
High Pass
Filter
Overall Time
Constant
1 Hz 0.16
5 Hz or above 0.045