tdms

[rick.paquet@takata.com]

My tdms files are too big for excell to be effective at viewing the entire waveforms. I'm considering DIAdem for the future. For now, I just need to pull certain time slices of the waveforms into excell. How should I pull these specific pieces?

[Herbert Engels]

I don't think you can do that with the Excel Add-In that we provide for TDMS.  You would have to create a TDMS file that only contains the subset of data you want to look at. That can be done pretty easily by opening the original file, reading your data subset (using the "count" and "offset" terminals on "TDMS Read") and putting that data into a new file.

You might want to check out the TDMS File Viewer VI, because the TDMS Viewer comes with a similar feature (use the "Settings" dialog to specify your data range). The VI is not password-protected, so feel free to have a look at how it is implemented.

Hope that helps,
Herbert

[rick.paquet@takata.com]

Thanks! I was inspired by the viewer but it's not flexible enough. My tdms file contains a 1-D array of waveforms(DBL). How do I convert time to # of bytes of that?

[Herbert Engels]

Not sure I understand the question.
- What were you trying to do that the TDMS Viewer wouldn't let you do?
- I assume that by time, you mean the T0 of the waveform. What number of bytes are you looking for? (the width of the timestamp is 128bit, but I don't think that's your question ... )

Herbert

[Herbert Engels]

Wait, I think I understand. There's an error in the documentation that states that offset and count are in # of bytes. In fact, both are number of values, so you don't need a conversion.

Herbert

[rick.paquet@takata.com]

That should be perfect. I will try that assumption.

[rick.paquet@takata.com]

I would like to view waveforms stacked in one window. Unless I've missed the point, one weakness of the viewer allows only one wave for view.

[Herbert Engels]

You can view either everything in the file, or everything in a group, or a single waveform. You cannot view an arbitrary selection of waveforms. Touché

Herbert

[rick.paquet@takata.com]

Herbert,

I'm brand new to Labview so all the one on one is appreciated. How can I select the waves to pull from a TDMS?

[Herbert Engels]

You can wire the group name and either a single channel name or an array of channel names to "TDMS Read" in order to load a particular group of channels. You can use "TDMS List Contents" to get a list of the groups and channels that are in your file.

You might want to have a look at some of the TDMS examples (e.g. Write/Read Event Data) and this document to learn more about how to use the TDM Streaming API.

Herbert