Check the listing for details. National Instruments NI 9233 cDAQ IEPE Sound and Vibration Input Module. Condition: Used. Listed at 895.00 USD. National Instruments 9233 simultaneous analog input module for cDAQ / cRIO systems. Tested, fully functional, and in excellent physical condition. Designed for use with IEPE-compatible sensors. Similar to the current 9234 model, but the IEPE excitation is always enabled. See NI application note for details. The 9233 module is supported by NI-DAQmx versions 17.5 and earlier. Each channel has a BNC connector to which you can connect an Integrated Electronic Piezoelectric (IEPE) sensor. The center pin of the connector, AI+, provides the DC excitation and the AC signal connection. The shell of the connector, AI–, provides the excitation return path and the AC signal ground reference. For additional information and resources, use the model name to search the manufacturer's website.