how to display a binary file

[trannh]

Hello,

I am working on creating program that lets me display data I've collected and stored in a binary file. Here is the code (+pic of the program) for collecting and storing the data. Data will be recorded on multiple channels (possibly 4 channels). The program I've attached can display the data in real time as data is being collected. My issue is just to call back all the data and display it in a graph that shows all the data from all channels. I'm stuck on creating this display program. Any help would be greatly appreciated.

Thank you

[billko]

Can you write it to a TDMS file instead?

http://www.ni.com/white-paper/3727/en

[crossrulz]

I would use the Stream to TDMS option for DAQmx.  If you go into the LabVIEW Example Finder and do a search for "TDMS Logging", you will see a few examples for DAQmx on how to set this up.  It is very easy to do and works great.  And then to view the data later, there is a TDMS Viewer VI in the File I/O->TDMS palette.

[trannh]

Thank you very much to billko and crossrulz. Very useful information. TDMS format seems to be the best option since I will need to access the data I'm recording for analysis and review. However, I don't think the Labview I am using is up to date and may not have the TDMS palette. I believe I'm using Labview 7.1, which is really old. I'm going to try to get the new version, but if I cant and must work with a binary file, do you have any suggestion on how I could display that type of file on a graph? Thank you

[billko]

Bummer...  I guess it was introduced with 8.2?  I have to rethink this then.

[trannh]

I believe so Bill. I'm still working to see if I can get a newer version of Labview to make it easier. I would still like to be able to work with the binary file to display the data. I was also thinking of saving the data into an ascii file, since I could use Excel or MatLab with such files. Not sure about size limitations with ascii files though, since there's going to be a lot of data recorded. Do you think this is plausible?

[Pete.Dunc]

The way that data is stored in disk in LabVIEW is documented.  Check out the waveform datatype in this help file.

I had a fairly indepth discussion about this with someone who wanted to use this to do a 'random access' read of the variant attributes of a waveform, without loading the whole thing.

It's fairly deep in the grass, but then again you are dealing with 1's and 0's

[Pete.Dunc]

The last post in the thread I mention has an Excel file with the binary makeup of a waveform.  It may be worth taking a look at that - or you could unbundle the components and log seperately, would make it a little easier to decompose.

[trannh]

Thank you Peter for replying back. I read about the waveform data type and I think I understand some of it, but it's still quite confusing to me. I understand the code for the datatype, but I'm unclear about how I can use that information to recall the data I'm recording for analysis. I'm still very new with Labview, so a lot of this is confusing for me. I'm sorry about that and I really appreciate everyone staying patient with me. I mentioned in an ealier post about saving to an ascii file. Do you think this could work?

[Todd_Lesher]

Have you tried breaking the data apart before writing to file? Iterate through the 1D waveform, iterate through the samples, etc. It might be slower, though.