Paul,
It sounds like you are running into the situation where the resolution of the ADC converter is the source of the behavior you see. Your configuration may be set so that a voltage change is not seen between samples, generating multiple points with the same value. If this is the case, the graph you see is correct. It is displaying the points it receives from the FP-AI-100. You can verify this by displaying the graph data in an array, and seeing if some of the adjacent samples show the same value.
If this is the case, see if you can match the signal range to that of the ADC to take advantage of the resolution available. For example, if you set the range to be 0 to 30 volts, the smallest detectable voltage change would be 7.3 mV (range/gain*2^resolution) bec
ause the FP-AI-100 has a resolution of 12-bit. You can read up on issues with range and resolution by doing a search on http://www.ni.com using the keywords "range" and "resolution".
Otherwise you may be able to compensate for this behavior in software, such as running an averaging routine or applying a mathematical formula to the data points.
Hope this helps!
Wilbur Shen
Applications Engineer, Web Support
National Instruments
