Manual

Publication GMSI10-UM013D-EN-P - May 2010
Configuration Parameters 69
Speed Measurement Parameter
Use the speed measurement parameter to configure the filtering performed on
the speed measurement.
gSE Parameters
Use the gSE parameters to configure the gSE signal processing and gSE
spectrum measurements for channel 1 and channel 2. The gSE parameters are
configured independently of the (conventional) channel signal processing and
spectrum parameters. There are two instances of the gSE parameters, one for
each channel.
Speed Measurement Parameter
Parameter Name Description Values/Comments
Exponential Averaging Time
Constant
Sets the 3-dB bandwidth for the digital filter used to
calculate the Speed Value and Acceleration
Measured Value. The 3-dB bandwidth is roughly
equal to 1 / (2
π x Exponential Averaging Time
Constant). The greater the value entered, the longer
the response of the measured Speed Value and
Acceleration Measured Value to a change in the
input signal (less sensitive to noise in the signal).
See example table below.
Time Constant
(milliseconds)
-3dB Frequency
(Hz)
Settling Time
(milliseconds)
5 31.8310 11
10 15.9155 22
20 7.9577 44
50 3.1831 110
100 1.5915 220
1200 0.1326 2640
IMPORTANT
The XM-122 can produce gSE measurements only with an
accelerometer. The gSE
measurements are only available
for the channel when Eng. Units is set to "g." Refer
to Channel Transducer Parameters on page 58.