I am trying to display a dc voltage from a dc voltage supply using labview. All researched examples and a few attempts have displayed the dc voltage as a square wave. I have used "DAQ Assistant," "NI-DAQmx" and refrenced examples including "Cont Acq&Graph Voltage-Int Clk.vi", all of which have displayed my constant voltage input as a square wave. My problem with this is that I have tested and have proven that the voltage source is outputing a constant voltage. Let's say the output voltage from the source into the DAQ is 4.0 Volts. If this was occuring, the graph as indicated by the "DAQ assistant" or "NI-DAQmx" VI would be a square wave with 4.0 Volts as the amplitude and bottoming out at 0.0 volts, but it would continue to oscillate between these two values. In the DAQ assistant, if you use the table as an indicator instead of the graph, the value would fluctuate from 0 to 4.0 Volts. Again, the problem with this is that the source is never outputing any value other than 4.0 volts. Now - the sampling rate and number of samples DO change the results. A higher sampling rate would make the time between the amplitudes smaller, coming closer to the desired output of a horizontal line at 4.0 volts. That is pretty much all, but I would like to point out that every example from every source that I checked for "analog DC voltage input measurement" displayed the results as a sninusoidal graph.
