Signal distortion in Voltage Measurement

Hello,
I am using PCI-MIO-16E4 for voltage measurement from a Single phase
voltage supply panel. I use CB-68LP as connector cable. When I see the
output signal using Scope it is giving exact value and pure sinusoidal,
but when it comes to LabView 7.1, the magnitude is correct and the
sinusoidal is distorted. The siganal is not continuous and looks like
triggered pulse in the middle for every cycle. So, the signal breaks
goes up like a sqaure pulse and comes down, sinusoidal continues. I
donno if there is any problem with the triggering options which i
didnot selected. I am very new to labView. The example file I am using
(obtained from example finder/DAQMx/Voltage) is attached below.
Any help is appreciated.
Thanks
Attachments:
Cont Acq&Graph Voltage-Int Clk.vi ‏68 KB

Hello Serges,
Thanks for your response and suggestions. Let me explain my problem more clearly. I am using channel 6 now for measuring Voltage so I have connected wires to pins 25,58 on CB-68LP from the transducer output. These numberI obtained from LV itself from connection diagram and also from other thesis works and weblinks.
I am getting the right signal intially for sometime when i see both in the scope and in the LV using our DAQ with the above specified connections. It is same for all other channels. I am measuring in the differential mode only (Can you suggest me if this mode is wrong and where to change the setting in 'vi' attached) and verified it in the test panel too. After a couple of minutes the signal is getting distorted in LV as well as in MAX also as attached above. But in the scope it show the same sinusoidal without any kind of distortion. I feel the problem could be with the Connector block or connecting wire or my LabView file. The DAQ card is really new which we got 1 week back from NI. I will attach the right signal preview with this post.
Attachments:
correct1.jpg ‏2305 KB

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