Shock Accelerometer
Page 14
002-096e-01.19
7.1.4
Sensor Power-Up
Figure 10:
Behavior Of The Output Signal During Power-Up
When power is first applied to the sensor, (through an AC coupled
coupler) a voltage will appear at the output of the coupler (See Figure
10). As the coupling capacitor discharges, the DC output, from the
coupler will drop to zero Volts. This "settling time" is equal to 5 times
the time constant of the coupler employed. Allow time for the unit to
"settle" before making measurements.
7.1.5
Overload Recovery
Figure 11:
Output Behavior During Overload and Recovery
Whenever the impedance converter is driven by a signal exceeding
the normal operating range, certain components will become non
operational. During this non operational state, the amplifier
components are protected from overload damage. The amount of
time required for recovery from an overload depends on several
factors. Important for overload recovery time is the size of the
overload. As with power-up, the time constant makes the biggest
contribution to the recovery time. Figure 11 illustrates a typical
overload and recovery sequence.
7.1.6
Supply Voltage Effects
Long-term fluctuations in the power supply level between 24 and 30
volts can be tolerated. The sensitivity shift caused by such deviation is
less than 0.05%/Volt. A normal noise level is maintained if the power
supply ripple is 25mV RMS or less. The polarity must be maintained
throughout the system since applying reversed polarity power may
cause damage to the accelerometer.
