Document reference MAMPS-HW/E HARDWARE MANUAL
Edition 18 - March 2022 VM600 machinery protection system (MPS)
7-5
Tracking (narrow-band vibration analysis)
PROCESSING MODES AND APPLICATIONS
7.3 Tracking (narrow-band vibration analysis)
(1) Description
The tracking technique allows specific machine vibrations to be isolated and followed, for
example a particular shaft speed. This is a useful tool for machine condition monitoring,
particularly for the surveillance and balancing of critical, variable-speed, multiple-shaft
machines such as gas turbines.
(2) Block diagram
Principal features:
• Calculation of 1X, 2X, 3X, 4X amplitude and phase, or amplitude only (if no 1/REV input)
• For analysis, calculation of 1/3 X, 1/2 X amplitude
• Wheel teeth can be set in the range 1 to 255
• Configurable fractional tacho ratio, where the multiplier (numerator) and the divider
(denominator) can be set in the range 1 to 65535
• Tacho range input from 0.3 Hz to 50 kHz
• Narrow-band filter with a high Q-factor (Q = 28)
Note: The Q-factor of 28 is a fixed value (hard-coded constant)
• Acceleration output (g, m/s
2
or inch/s
2
)
• Velocity value processing (g, m/s
2
or inch/s
2
converted to mm/s or inch/s).
For a given harmonic, the processing outputs the amplitude and phase. However, the phase
is available only if the 1/REV input is present.
The tracking processing is able to operate in the frequency range 0.1 Hz to 10 kHz.
Vib.
input
Narrow band
(DFT rectification)
Output 1
amplitude
value
Scaling:
RMS
Mean
Peak
Peak-Peak
Alarm level
detectors
Output 1
amplitude
alarm
Output 2
phase
alarm
Output 2
phase
value
Tacho or
1/REV
Ampl.
Phase
DIV
Figure 7-2: Block diagram showing tracking (narrow-band vibration analysis)
processing
Note: DIV = Number of wheel teeth x (multiplier / divider)
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