RT DAQ Phase difference measurement

[eesen]

Hello,

I try to develop an application under LabVIEW Real time.

I have DAQ cards PCI-6289 and PCI 6143

I want to measure phase difference of two signals read from analog input channels of DAQ cards.

I search for a solution in the forum but i can't find a good one for my application. I don't want to use express vi to measure phase difference since they consume long time:( Real time programming tips advice not to use them.

Any suggestion/ solution is welcome

[Jeff_T.]

Hello,

I would start with the example program Cont Acq&Graph Voltage - Int Clk.vi.  You can change the "Physical Channel" control to include all of the channels from one device and the data will be returned as an array of multiple waveforms or a 2D array of doubles.  You can extract the data from the waveforms using the "Get Waveform Components" node.  You would then be free to implement any phase comparison logic that you would like.  

Give that example a look and let us know if it doesn't fit your needs.  

Best Regards,

Jeff Tipps
Applications Engineer
National Instruments

[eesen]

I don't want ot read sample as waveform for some reasons. I read as double numbers. Must i read sample as a waveform in order to measure phase shift.

I look all example coming with labview 8.2 I start my application by using them. But they are base application. Exmples found in forum didn't work either. I'm measuruing a changing phase:(

[eesen]

I find a solution myself:)

The attached example works well. Perhaps it will helpful for somebody