Commtest Instruments vbBalancer - Assigning Sensors to Channels

Section 6: Analyzing Measurements Onsite
69
Store Units Max dB Value
Linear Scale
Max dB Value
Log Scale
Acceleration
m/s
2
, mm/s
2
m/s
2
, mm/s
2
Velocity
mm/s, µm/s mm/s, µm/s
Displacement
mil, mm, µm mm, µm
Store Units Y Axis Fixed
Linear Scale
Y Axis Fixed
Log Scale
Acceleration
automatic, current, mm/s
2
m/s
2
, mm/s
2
Velocity
automatic, current, µm/s mm/s, µm/s
Displacement
automatic, current, m mm, µm
vdB
The vibration velocity level vdB is defined as 20 times the logarithmic
of the ratio of the RMS velocity level to a reference velocity value
(the vdB reference). The value 1e-6 mm/s is an abbreviation for
1x10
-6
mm/s and is the SI reference level. The value 1e-5 mm/s is
the reference level used by the US Navy and many American
industries.
adB
The vibration acceleration level adB (US) is defined as 20 times the
logarithm of the ratio of the RMS acceleration level to 1 µg RMS.
The SI version of adB is less commonly used, and has a reference
value of 1 µm/s
2
.
Setting the RPM
Setting the 1X RPM allows you to view the chart in orders (for
spectra) or revs (for waveforms). You can enter the RPM manually (if
you know it), or set the RPM from a spectral 1X peak.
Entering the RPM manually
• With a measurement displayed press
then Set
RPM.