Section 4 - Power Requirements; Power Supplies - Omega ACC320 User Manual

SECTION 4 • POWER REQUIREMENTS
The low impedance type of accelerometer must be powered by a constant
current power source. Modern data acquisition systems (oscilloscopes, FFT
analyzers, data collectors, etc.) often have this constant current power supply
built in.
The power required to drive the accelerometer is typically 2-4 mA at either 15
or 24 volts. Please refer to the specifications describing your particular model
for clarification on its power requirements. Further note that all OMEGA
accelerometers will not be damaged even If the power supply provides
constant current as high as10 mA or voltage as high as 30 volts. Incorrect
powering may impede some of the operating characteristics such as dynamic
range, temperature range and noise level.
You should take care not to exceed the 10 mA current limit. If a custom power
supply is used, it must incorporate a 2 mA constant current diode in series
with the output to insure that the accelerometer Is not over-powered.

POWER SUPPLIES

If the data acquisition system being used does not incorporate its own
power supply then a separate power supply must be used. OMEGA
manufactures single channel and multiple channel accelerometer power
supplies.
Low impedance accelerometers do not require much power and it is
preferable that a very low noise regulated power supply be used. For this
reason, it is often appropriate to use a battery powered unit for powering the
accelerometer. The battery-powered unit offers the cleanest (low noise)
characteristics and can be offered in either
battery pack versions. Regulated line power supplies are also available for
these applications where power must stay on for extended periods of time.
Please refer to the appropriate sales bulletins and operating manuals provided
for each OMEGA power supply. Figure 4-1 illustrates how a low impedance
accelerometer should be connected to a constant current power supply. This
schematic diagram shows the basic components within the accelerometer and
power supply.
Figure 4a. - Low Impedance Accelerometer Interconnection
NiCad rechargeable or disposable
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