8-channel, 51.2 kS/s/ch, -5 to 5 V, C Series Sound and Vibration Input Module The NI-9231 is a high-density sound and vibration module capable of measuring signals from Integrated Electronic Piezoelectric (IEPE) and non-IEPE sensors such as accelerometers, tachometers, and proximity probes. The module can perform the high dynamic range measurements required by modern microphones and accelerometers and features simultaneous sampling capabilities. The NI-9231 integrates a TEDS input path and a 2 mA IEPE signal excitation source, both of which can be enabled and disabled, thus eliminating the need for external sensor power supplies and reducing the complexity of the data acquisition system.