There are two primary types of accelerometers: one is the ICP (integrated circuit piezoelectric) having voltage output, and the other is known as a CLD (current line drive) type, with a current output. The standard ICP accelerometer has a nominal output of 100 mv/g and the output of a standard CLD accelerometer is 9.81µA/g.
Cable movement during low frequency measurements with ICP accelerometers can induce triboelectric noise. Triboelectric noise results when two materials are rubbed together creating an electrical charge between them. Triboelectric noise can be generated by flexing or vibrating the accelerometer cable during data acquisition. Such movement can result in friction between the cable’s various conductors, insulation, and fillers. This friction can generate a surface charge resulting in triboelectric noise. Vibration data collectors will measure the voltage generated by this effect. This can cause data integrity issues with acquired data. CLD sensors output current rather than voltage and are therefore not subject to the triboelectric effect from cable movement.
Vibration Analysis by Gary James CRL