Measurement Computing WavePort rev.3.0 - Manual (Page 133)

Appendix A, Using Accelerometers 04-06-00 A-3
Power Supply Effects
The nominal power supply voltage recommended by most manufacturers is 15 to 24 V. Units may be used
with voltages up to 28 volts. Sensitivity variations caused by voltage change is typically 0.05%/volt.
Power supply ripple should be less than 1 mVrms.
Connector
This parameter specifies the connector type and size (4-48, 6-40, 10-32 coaxial etc) and the location on the
sensor, that is, top or side (usually on the hex base). Where there is no connector on the sensor, an integral
cable is specified with the length and the connector, that is, integral 6-ft to 10-32.
Electrical Grounding
Case-Grounded Design
In case-grounded designs, the common lead on the internal impedance matching electronics is tied to the
accelerometer case. The accelerometer base/stud assembly forms the signal common and electrically
connects to the shell of the output connector. Case-grounded accelerometers are connected electrically to
any conductive surface on which they are mounted. When these units are used, take care to avoid errors
due to ground noise.
Isolated-Base Design
To prevent ground noise error many accelerometers have base-isolated design. The outer case/base of the
accelerometer is isolated electrically off ground by means of an isolation stud insert. The proprietary
material used to form the isolation provides strength and stiffness to preserve high-frequency performance.