4.
To set the Wideband filter, make the configuration changes as displayed in the following screen.
5.
If the LM 1X Tracking Filter is desired, then navigate to the
Variables
tab. Select LM_RPM_A and attach a variable
containing the 1x Harmonic frequency of 150000 RPM to it.
Note
LM 1x Tracking Filter frequency input is always RPM, even for CDM applications. Be sure to convert the target
frequency from Hertz to RPM.
If the YVIB firmware is receiving the data correctly after this configuration, then the following is expected:
• Gap values are passed through a 2-pole, low-pass filter with a cutoff frequency of 8 Hz. This will attenuate the AC
waveform by at least 4000:1, and the DC component of 12 V DC will be unaffected. Since the units for GAP1_VIB1 are
always Volts, and the 4000:1 reduced AC wave will be ±0.0005 volts, the GAP1_VIB1 value will be -12 ± 0.0005 Volts.
• The DC removal filter will eliminate the DC component of -12V. The 500Hz, 1 V
PK-PK
and 2500Hz, 1 V
PK-PK
AC waves will
pass through the wideband filter unaffected and be sent to a 160ms capture window, which will capture 80 cycles (scan period
* frequency of the lowest principle). The RMS value computed for this input (sum of ideal sine waves) will return 0.5 V
RMS, which will be converted to PSI. Therefore the VIB1 value will be 5.0 PSI RMS.
• LMVib1A value is the magnitude of the 1X harmonic of the rotor speed in LM_RPM_A, which is 2500Hz (150000 RPM).
Since the input wave is the sum of two ideal sine waves, one of which is at 2500 Hz with a magnitude of 1 V
PK-PK
, the value
of LMVib1A will be 10 PSI
PK-PK
.
YVIB Vibration Monitor Modules
GEH-6855_Vol_II System Guide 261
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