Vibration Displacement; Vibration Displacement Input Processing; Wideband Vibration Scan Period - GE Mark VIeS System Manual

8.3.3.3 Vibration Displacement

Inputs 1-8 support Proximitor sensors to collect air gap, wideband vibration, and 1x/2x vibration vectors relative to a specified
Keyphasor channel. In Heavy Duty turbine applications, Proximitors are used to monitor the position of a rotating shaft.
Vibration Displacement algorithms report a filtered air gap value, and peak-to-peak displacement value, and an optional
vibration phasor relative to a specified Keyphasor channel.

Vibration Displacement Input Processing

GAPn_VIBn – The filtered Position or Gap value in engineering units (EU).
Gap values are filtered through a 2-pole, low-pass filter with a fixed cutoff frequency of 8 Hz. The output of the gap filter is
passed through a rolling average filter prior to scaling. Gap Values are converted from Volts to EU. For Vibration
Displacement applications, Gap values are magnitude quantities, so they are always positive.
Gap
V
PROX
Filter
VIBn – Wideband Vibration Displacement (Peak-Peak) in engineering units (EU).
Wideband vibration information is passed through a variable scan period peak detection function. The length of the peak
detection is determined by the Keyphasor 1 detected speed in RPM.
Shaft speed (RPM)
0 – 60
60-480
480-2250
>2250
Attention
The output of the peak detection function (V
V is converted from Volts to EU. For H1B systems, a lower latency peak detection function can be enabled by changing
PK-PK
the OperatingMode parameter to Enhanced. This function will update every frame, instead of every scan period.
Note Sensors monitoring position of rotating elements typically measure Peak-to-Peak. RMS calculations can be used
instead if needed.
VIB_1Xn, VIB_2Xn – Vibration Phasor Magnitude (Peak-Peak) for 1st/2nd harmonic of Keyphasor frequency in engineering
units (EU).
Vib1xPHn, Vib2xPHn – Phase Angle between Keyphasor and VIB_1Xn/VIB_2Xn vibration phasor in degrees.
YVIB Vibration Monitor Modules
V V
FILT GAP
Mvg
Avg
Filter

Wideband Vibration Scan Period

Peak Detection function always uses KPH1 RPM, even when the sensor is configured
to use KPH2 for 1x/2x Vibration Phasor calculations.
) is passed through an adjustable 1-pole, low-pass filter prior to scaling.
PK-PK
Public Information
EU
GAP
A/B abs (A)
A A
B
Scale(V/EU)
Scan period (ms)
160
2000
250
160
GEH-6855_Vol_II System Guide 249
GAPn_VIBn
|A|