Amateur Hour: Let's fix this graph of voltage vs. time!

[Stephen L]

Hi there,

I'm still getting my feet wet with LabView, and I am trying to make a graph of Voltages Vs. Time for voltages recorded using an A-D board. The VI records fine, the only amateur issue I have is with getting the VI to properly plot (and autoscale, if possible) the voltages with respect to time. I've looked at the example VI's, and I made something that (I thought) would work, but alas it doesn't!

Where did go wrong?

Thank you!

[Dennis_Knutson]

You are not plotting voltage versus time. You are plotting one channel versus the other channel. You don't need an xy graph to do this and you certainly don't need the picture control. All you need to do is use the normal waveform graph. If you were using an NI DAQ board and it's more sophisticated driver, you wouldn't have to do anything special. The NI driver will automatically add a timestamp. There's several ways you can add time information to a graph. Attached is an example that uses the build waveform function. The waveform data type is the type of data that is returned by the NI DAQ driver so you can get an idea of what extra code you have to write by using someone else's hardware.

[mikeporter]

You are getting too complicated. If all you want is an XY plot you don't have to use a picture control, just use (surprise!) an XY plot indicator. Are both the values read inside the loop Y-axis values or is one of them the X-axis values? If they are both Y values all you have to use is a waveform graph indicator.

Mike...