Thanks for responding so quickly. What you've said helps in that your example is almost a carbon copy of what I've already been trying. The only real difference is your example uses two randomly generated numbers to simulate x and y whereas I'm trying to use two DAQmx tasks. That leads me to believe that maybe there is something wrong with how I'm acquiring my data. I spent all of today on this and most of that time has been spent just trying to find the best way to get two different channels worth of voltage into a vi. My original thought was to use two tasks created in MAX via two DAXmxRead vi's. That is how things appear in the attached vi (Labview 7.0).
The other thing I tried (which was so much easier) was to use the DAQAssistant to pull in both signals at once, then use a seperate SelectSignal Express vi to grab each individual signal. So far so good, but now I have a dynamic data type, and I'm not sure how to break that into the two 1D arrays I'll need for the cluster into the XY Graph. Is there a preferred way to grab signals? In this application, high speed really isn't a huge issue as I am applying a pulling force to a part until it breaks. Still I want to be able to see this on the graph and pick out what the maximum pull was (force) at point of breakage and also know how far the pull had progressed (lvdt).
By the way, you were correct about not needing 2D arrays for the XY Graph, I guess my brain just combined the two 1D arrays for me!
Just like the DAQ Assistant, you can use DAQmx to read multiple channels with a single read. When you use the DAQmx Create Channels, your physical channels would be something like Dev1/ai0:1 (for continuous channels) or Dev1/ai0,Dev1/ai2 (non-continuous).
There are a couple of ways to use dynamic signals. You can use the Convert From Dynamic Data to get a scalar, array, or waveform. You can also use the Split Signal function. Also, the Express XY Graph (add from front panel) allows you to use dynamic data as inputs so the split signal would work well for that.
Did you mange build a force plot. I am a new user and got the same problem that you had that time.
could you help me out.