I want to acquire 3 signals continuously point to point using single daq card in labview .when i tried to acquire 3 signals only one channel is activating and other 2 channels are not acquiring .please if anyone knows post the answer.
Yes sir my problem related to hardware only .i want to acquire 3phase signals at a time using continuous sampling and multi channel with only 1 daq card .I am using NI USB 6009 DAQ CARD.
The NI USB 6009 DAQ card is limited in function but it should be able to perform continuous signal acquisition of multiple channels. Use the NI DAQmx Assistant in LabVIEW and select the three channels when prompted. I assume you may have done this already and that is where the issue is.
Attempt to acquire signals from an oscilloscope or battery on the three lines and see if they are activating. If they are not, then maybe you have a faulty daq or wrong acquisition settings. If they are acquiring, then maybe your original signals are faulty.
It may be that the signals are the same value and so are showing in your graph as one signal. So it would be good to split it. From the DAQmx assistant output, use the "convert from dynamic data type" tool and set your output to be 2D array or scalars (not sure if it is rows or columns are the channel but play around with it. Then add an index array tool to split the signal into three arrays (index 0, 1, 2) and feed the three output to three charts or numerical indicators.