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Certain models of signal conditioners have Meters or LEDS, which enable users to monitor the
bias voltage output signal, check microphone operation, and detect cable faults. Normally, a
“yellow” reading indicates an open circuit (e.g., a disconnected cable); “green” indicates normal
operation and a “red” reading indicates a short circuit (e.g., a shorted cable). The signal
conditioner provides a zero-based, AC-coupled output signal that is compatible with most
standard readout devices.
Today, many FFT analyzers, data acquisition modules, and data collectors have the proper
constant-current excitation built-in for direct use with ICP
microphones. Before using this
feature, check that the supply voltage and constant current are within acceptable limits for use
with your particular microphone. (Check enclosed
Specification Sheet
.) Consult the Vibration
Division’s product catalog for more information about signal conditioners.
4.0
Installation and Operation
4.1.
Mounting Methods
Consider the expected air flow across the surface on which the Surface Microphone will be
mounted to determine the best way to secure the microphone to the surface. See Figure 4. When
no air movement is expected, the double-sided adhesive pad, trimmed to the size of the
microphone if desired, is adequate. For low air flow speeds, such as on the side of a vehicle,
include the Fairing along with the double-sided adhesive pad to mount the microphone. At
moderate to heavy air flow speeds, such as in a wind tunnel, add the single-sided adhesive pad
on top of the Fairing. See Figure 5. Regardless of the mounting method, the Surface
Microphone’s profile will not exceed 3.2 mm.
NOTE: Under no circumstances
should a voltage be supplied to an
ICP
microphone without a
current-regulating diode or
equivalent electrical circuit. This
may include ohmmeters, multi-
meters and continuity testers.
Damage to the built-in electronics
resulting from the application of
incorrect power, or the use of an
unapproved power source is NOT
covered under warranty.
Figure 3
Microphone
Signal
Conditioner
Readout
Summary of Contents for 130B40
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