Configuring a NI 9219 to measure AC Voltage

[DonaldKM]

I am trying to configure a NI-9219 to read an AC voltage and display a waveform to show phasing relationships between excitation on the primary and voltage prodced on the secondary of an LVDT. The excitation is a nominal 78 VAC 400Hz and the maximum secondary voltage is a nominal 18 VAC. I am using a 115/26 VAC stepdown transformer for the excitation prior to the input of the NI-9219; however no luck in aquiring any signal. Any help would be appreciated along with some clarity on the following questions:

1. How do you configure a Ni-9219 channel to aquire and read an AC voltage?

2. Are the minimum and maximum settings peak or RMS?

3. What is the maximum peak/RMS AC voltage that cam be raed; the manual states high voltage as 42.4 Vpk or 60 VDC?

Thank you.

[DonaldKM]

Spoiler

Update: I was able to aquire a signal by setting the device to High Speed vice High Resolution; however I am unable to achieve a steady signal like one would expect when read using an oscope.

[Jason-H]

Here is a white paper on creating a virtual channel and using it in LabVIEW, http://www.ni.com/white-paper/5375/en/. The minimum and maximum settings should be peak, and yes the max voltage is -60 to 60 VDC. Also, could you clarify what you mean by not getting a steady signal? A screenshot may be helpful.

[DonaldKM]

Thanks for replying. I am going to use a pair of Ni-9225 to read the AC voltage, since it appears that it is set up for that type of measurement; this will also allow me to read the 78 VAC excitation without the need to reduce the voltage. I read the white paper and watched the video; however I feel that in this case I am using the wrong module to perform the task. The steady reading was refereing to the fluctuation of the aquired siganl, the sample would fluctuate at the rate of the DAQmx setting and what I need is measured reading as if you were using a multimeter for RMS or an oscope to show sine wave and phasing as well as RMS of the peak. I think the Ni-9219 is designed for a DC voltage and provides the ability to measure any AC ripple on that signal.