how can I make this vi run faster?

[Joe_H]

Is there any real reason to have modified the Read waveform VI so much. It really did everything that you wanted. You could have just put the data manipulation part that you changed in a Subvi. That would have been much easier. At this point if you can live with the speed. I would not try to modify it to much more. You have 1 VI that will grab all 4 channels already. Besides to do the VISA calls to get all 4 waveforms would just the same code duplicated 4 times anyway.

[Coq_Rouge]

I do not know how you are configuring your scope. But in worst case you may risk getting 4 curves from 4 different trigger events. And in that case your setup is pretty much worthless for any research. I have done some changes, and at least now the 4 curves is related to the same trigger event. Programming a scope is not so hard. You will find the "programmers manual" here http://reld.phys.strath.ac.uk/local/manuals/TDS640Aprog.pdf

Here is a scope primer I think you should read http://www.testmart.com/webdata/appnote/1603.PDF

[bonesaw]

Yes, that vi is better for research purposes. Thank you for looking into that for me. Now, I also use matlab to download traces from the scope, and when matlab does it, all four channels are downloaded at the same time (not sequentially and under the same trigger event). The read waveform vi for the tds 540 is from what i understand only able to read one channel at a time, but it is hard for me to belive that there is no way for labview to download all four channels at once. In the scope manual it says you should be able to put each channel in the code separated by commas (DATA:SOU CH1, CH2.....;), but as ive been saying i could not get it to work.

[Coq_Rouge]

I think the driver that labview provide is more a push in the right direction. It is not meant to be a full application. But you should be able to write a function for the curve command. It is more about sending the correct commands