How can I view data continuously?

[cwalmquist]

I have an application where I need to log data for a period of about 1 - 2 minutes at relatively low speed (100 Hz).  The end of the test is determined by visually examining the signal, looking for the desired characteristic and stopping the acquisition.  I there a way to get SE to show the trace as it is being generated?  I know that I can set the number of samples low enough that the display updates periodically, but I can only find a way to show that chunk, not the whole signal since the start of the logging run. 

I had previously done this with a custom app using measurement studio strip chart, but now need to find a way to do it with SE.

Thanks for any help.

Charlie Almquist

[Phil_J1]

Hi Charlie,

As soon as you start recording, a new logged signal should appear in the project view, in the bottom left corner of the application under the "Logs" folder. You should be able to open that hierarchy and find your logged signal, then drag that signal into the main data view. The data view should now have a large viewer showing you the current chuck, but the small viewer below it (called the Preview) should be showing you the whole log since its beginning. At this point, the viewer is in "tracking" mode, which means that it will show you the new data as it generated. Using the Preview, you should be able to zoom and scroll through the log as it is being recorded to inspect the data, using the small cursors on the Preview to zoom or the scrollbar to pan around (doing this automatically sets Tracking off, but you are still recording). You can also right-click on the Preview for more options. When you are done zooming and want to return to the Tracking mode, simply select the "Track Logging" option from the Preview's right-click menu.

Does this help at all?

You'll notice that there is a "Show all" option in the Preview's right-click menu, but it is only a one-time action and rather than continue showing you all the data as it is being recorded, it only shows you all that data that had been recorded up to that point. I will make a note to add that ability in a future release. You can select the show all option as often as you like, but I know this is not ideal. Sorry.

Phil

[cwalmquist]

Hi Phil,

Thank you very much for your insightful and timely reply.  It does help a lot.  It provides me with a work-around on some tests I'll be doing next week.

It's not ideal, but that's clearly an SE limitation.  I really appreciate your showing me how to get SE to something that will work for now.

I am a bit surprised at NI, though.  I thought that at around $700, SE would do something as basic as this.  I don't use Labview, but I have developed several apps with Measurement Studio and VB6.  And I also often use free software that comes with data loggers (like the Fluke Hydra and the Agilent 34970A), and all of them allow you to view the complete signal as it is recorded, at least in a strip chart mode where you can set the window size.  Seems so useful that I wonder why there aren't more comments on the board about this.  Watching your hard-earned data unfold before your eyes seems like a pretty basic thing.  Not needed in every situation, but I would think generally useful.

Fortunately, I'm still in the trial period for SE, so I haven't plunked down the bucks.  Still trying to figure out if the investment in the USB 6211 was worth it. 

Thanks again.  You've really made things easier for me.

Charlie

[cwalmquist]

While I'm asking newbie questions,,,

I added a step to export to an ASCII file (so my other analysis software can deal with it).  But it seems that SE generates a separate  file for each buffer's-worth of data.   Ouch.  Is there any way to have it (automatically) save the whole logging run?  It seems like a pretty basic sort of a thing.   I know that I can do this at the end of the acquisition, but it sure would be nice to be able to do this in one of the "steps", which I understand are to simplify the acquisition process.  I want to view the data as it is acquired, but don't want to deal will a bunch of data files at the end of the acquisition.

Any help appreciated greatly!

Charlie Almquist
 

[Phil_J1]

Hi Charlie,

You're right, I can clearly see your point. We do have that strip chart functionality which also does include a buffer size (window size as you called it) but for scalar (single point) values and not waveforms. So if you were able to configure your result to be in single point mode then you would be getting this functionality, but I don't know if that's possible for you.

Thank you very much for your feedback, and I've created a Suggestion Report to make sure that this functionality is added for waveforms in a future release.

Phil

[Phil_J1]

Hi Charlie,

That's a good question. There are 3 ways that I can think of for you to do this:

1) (Good) You could configure your Save To ASCII step's "Export file type" to be "Generic ASCII" (this will not keep writing headers in the same file), select "If file already exists" to be "Append", and you can configure the other options as you prefer. This will write all the data to a single file like you wanted while logging.

2) (Better) Don't use the Save To ASCII step, but instead, once your done recording, find your new log in the project window - that I talked about a few posts above - in the bottom right corner of the application window. Right-click on the signal and select "Convert To ASCII". That will convert the entire log to an ASCII format.

3) (Best) In the application menu bar, under "Tools >> Options...", under "Logging" there is an option to "Automatically export log to ASCII file". This will create an ASCII file of your log automatically once the full log has been created (basically the same as #2, but automatically). By default, it will put your text file next to you log. That path can also be set in the Options window. When right-clicking on that signal in the project window, there is also an "Open Folder" option which will take you to that file.

If hope that's what you were looking for.

Phil

[cwalmquist]

Hi Phil,

Thanks a bunch for the suggestions on the file save.  The last one I hadn't discovered, and it looks like what I need.  You've really helped a lot.

Charlie

[Phil_J1]

Hi Charlie,

So regarding that ability to view the enitre log while recording; we've added it to our upcoming release. What you'll be able to do is, while tracking, the option to track the entire log will also be available. Meaning that the current behavior will be the default, but you'll be able to select the option that you wanted in addition. I hope that you'll be able do with the current features until then.

Thanks again for your feedback,

Phil

[Les Bartel]

Thanks Charlie for asking the question and thanks Phil for providing an answer that meets my needs (continuous waveform display).  I'm looking forward to the release that improves on this.

 - les

[ImTired]

Any chance of that next release coming soon?

I have a similar problem.

Thanks!

Bill