PCIe-6320 Analog input

[dg_lbe]

Just purchased the pci - 6320 and accessories to monitor a analog sensor output.  When running the DAQ assistant the noise is approximately 100mV.  This is not great as my analog sensor has a 3.125 mV resolution.  The sensor output circuit has an unity gain buffer and a low pass filter.  Connections to the interface board is connected to Ain(0) and Agnd.  Do I leave Ain(1) open or should this be connected to ground?

[Tarek]

The resolution of your card is about 3mV if you're using the +-10V range, which is good enough for your sensor.

In order to reduce noise, you should do your measurements differentially. This document does a great job showing this.

Try connecting the sensor differentially between AI0 (AI 0+) and AI 8 (AI 0-), as per the snippet below., and see if the noise is reduced.

Hope this helps.