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VM-4424S/H Instruction Manual
(Compatible with Version 2.16 or later)
9. How to Fix the Pickup and Frequency Characteristics
When a vibration pickup is attached to a vibrating body, a single vibration system is
formed at the contact area, and the natural frequency of that system is determined. This is
called the contact resonance frequency.
The contact resonance frequency varies depending on the fixing method and contact state
between the base of the vibration pickup and the surface of the vibrating body, and
particularly affects the high frequency characteristics.
Pickup fixing methods include (1) Screw mounting, (2) Instant adhesive, (3) Double-sided
adhesive tape (thin and strong material), (4) Magnet, and (5) pressed by hand (Fig.9-1).
Piezoelectric accelerometers are suitable for high frequency and high accelerometers. So it
is necessary to fix by (1) screws or (2) instant adhesives for accurate measurement.
Since this
product normally uses a detector probe, the influence of the probe on the characteristics is
large, but it is possible to fully grasp the increase and decrease and tendency of relative
vibration for the same measurement object. Furthermore, by listening vibration sound, the
function can be complemented.
(1) Consider the fixing method if necessary.
(2) If the tip contact surface of the detector probe is inclined, correct measurement cannot
be performed.
(3) The pickup may be damaged by a strong impact (1000m/s
2
). Please handle with care.
(1) Screw
(2) adhesive
(3) Double-sided tape
(4) Magnet
(5) Pressed by Hand
(6) Pointing Up or Angled
Fig.9-1 How to Fix the pickup
