Splitting Channels from DAQ Assistant + Real Time Data

[bmunden]

I'm running LabVIEW 8.0, and I'm using a National Instruments USB-6008 DAQ device.

I've used DAQ assistant to grab N samples from the DAQ device, and they are easily displayed on a waveform graph.  How can I separate these signals and use them to do arithmetic?  The voltages are from thermocouples and pressure transducers, and need to be multiplied by one another, as well as differentiated with respect to time.

Also, the graph displays only after the data is taken.  Can I accomplish all of this in real-time?  For instance, I'm looking to plot Y(t) vs. dY(t)/dt, where Y=AI1*AI3.

[bmunden]

I've tried "Split Signal" before, but the graphic doesn't splay into multiple lines, so I deduced that it has no idea what I'm telling it to do.

[bmunden]

I could index the array if I knew how:

a) DAQ Assistant forms the array

b) to write an index

[Dennis_Knutson]

The split signal function will allow you to get any channel you want. Then you can just use the multiply function on the selected signals. If you want multiple plots, you would then have to use the merge signals function. In the example below, the second and fourth channels are multiplied together and the other channels are plotted as they were acquired. A chart will display signals as they are acquired.

Message Edited by Dennis Knutson on 04-09-2007 09:19 PM

[bmunden]

Ok, LabVIEW nuance: Stretching the Split Signal graphic reveals multiple signals.

Let's say I wanted to display a pretty XY waveform graph in real time, and then ask the user if he or she wants to save the data once the graph is finished, could I do that?

[Dennis_Knutson]

Of course. There are numerous options for saving to file. Just look at the File I/O palette.. One of the easiest is the Write LabVIEW Measurement File Express VI.

[NT_Engineer]

Okay, I'm trying to do the same thing. Whenever I expand the split signals, It displays the multiple outputs.  However, I can only get one output node to connect to.  What's the appropriate way of doing this?

[Kevin_S]

Hi NT_Engine,

Were you able to build the example displayed above by Dennis?

When you say that you can only connect to one of the signal outputs, which one is it - the first one?  What do you connect to it?

Kevin S.

Applications Engineer

National Instruments

[AnalogKid2DigitalMan]

Looks like this discussion has 'Split' up into 2 different threads. Now we need to 'Merge' them here:

http://forums.ni.com/ni/board/message?board.id=170&thread.id=353249