Ac voltage measurements with ni 9219

Hello
i am trying to measure an ac voltage through lab view using NI 9219 module.for test purpose i have connected an Ac voltage source HI to pin #4 and Lo to Pin # 5. by setting up the DAQ assistant i plotted the output value of a 5 Vp-p sine wave.
i am expecting a sine wave but i can only get a straight line of few milli volts in the output graph(lab View).i am not sure if the NI9219 internally converts it to dc Voltage or i have some problems with the connection diagram.if NI 9219 has internal ADC converting the input to DC how can i de activate it so i can get an AC waveform
Please comment.
Thanks,
Ali

Well you have to sample a pure sine wave at a rate of at least twice its frequency otherwise you will not have enough resolution to properly reconstruct the original analog signal. http://en.wikipedia.org/wiki/Nyquist%E2%80%93Shannon_sampling_theorem More complex signals require even higher sampling rates (and fancy filters) to avoid aliasing issues.
The 9219 is a rather specialized module designed for strain gauges, thermocouples and other low-frequency application. Have you read its spec sheet and manuals??? http://sine.ni.com/nips/cds/view/p/lang/en/nid/208789
Using LabVIEW: 7.1.1, 8.5.1 & 2013

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I am updating an old LabView/Data Acquisition system that uses strain gauges to measure two forces (normal and axial) as well as two moments (Pitch and Roll). I am having trouble reading the voltage changes over my strain gauges using my NI-9219 as well as filtering the data with both a lowpass and smoothing filter. The program attached has the project and should have all the sub-vi's used in the program. This program was written on LabView version 8.5 and is being updated to a 2013 version of LabView. Also, the hardware previously used was a combination of a NI SCB-68 and NI USB-6251. If anyone could help me it would be greatly appreciated!
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Hi Coffeyfj,
Did you ever had this set up working? The first thing that I would do as I mentioned in the previous comment would be to use one of the LabVIEW examples. I recommended to you using the (strain - Continuous Input.vi). If you can read any voltage changes with the example vi, then we will know the problem we are having is in your code. If you cannot read any voltage changes using the example I mentioned, we can start trouble shooting the hardware connections. Are you connecting the excitation voltage? If yes, Are you making the right connections. Please refer to page 19 of the following document (half and full bridge modes)
NI 9219 Operating Instructions and Specifications - February 2009
http://digital.ni.com/manuals.nsf/websearch/4197ED4BD126E0B486257546005851CA
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Hi T.Knox,
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Good afternoon Nitin,
Thanks for contacting National Instruments with your issue, we'll try our best to resolve it for you as quickly and efficiently as possible.
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TanWal wrote:
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Dear RavensFan,
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"Have you tried swapping the modules between the slots and see if you still have the same problem or if it moves?" When I use the cDAQ 9178, I always use the first 2 slots next to the power suply and the usb connection, you mean that I should try for example the 4th and the 5th slot or other slots? I will try this on Monday, and I will let you know.
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I just re-read your original post. Why do you have the terminal setting to differential? This sounds like a single ended setup to me. Change the terminal setting to RSE. With a differential setting. you need to connect one source to AI1 and another source to AI9. The difference between the two will be reported. With RSE, only AI1 will matter and the voltage with respect to ground will be reported. Make sure you have your AO ground tied to your AI ground.
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Click to enlarge
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Ac voltage measuremen​ts with ni 9219

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Ac voltage measurements with ni 9219