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TDMS file taking too long to read/write

Hi,

I have successfully written/read from a 700 MB file within the same VI, but while trying to write even a smaller sized file at some other point on the VI, the process is too slow. I have "set property" for NI_MinimumBufferSIze but file size siding change.
I believe I set the property correctly as per the book. - don't know if I may have missed something else

[BADGE NAME]

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Hi blessedk,

 

Thanks for posting on the Discussion Forums to get some help with your TDMS writes. I was hoping to get a little more information on the issues you're seeing so I can best support you. Does the process execute for the same amount of time regardless of the file size? You say it is too slow- how large of delays are you seeing? Also, what have you set the MinimumBufferSize to? 

 

Hopefully this extra info will help us narrow down the solution. Thanks!

Austin H.
Applications Engineering
National Instruments
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I have two read/write VIs on my block diagram. The second write /read eventually executes but takes over two hours ( compared with the first write/read of 700 MB file which takes only a few seconds and did my even use any buffer) . Buffer size was set to 10000 in the second read/write

[BADGE NAME]

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Hey blessedk,

 

That behavior is definitely unexpected; have you been able to use highlight execution and pinpoint where in the code the bottleneck occurs? Are you making sure to close all references to your files before opening new ones? Are you receiving any errors when doing the write, or just the long delays?

 

If you can attach your code, that would be the best way to resolve the issue, so I can test it out on my end or see if there are any configurations you may need to reset. You can just attach it to your next post!

 

Thanks!

Austin H.
Applications Engineering
National Instruments
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Hello Austin. I have been able to find a solution to the long write duration. It appears to be mandatory that the data to be saved ( to be wired into the "data" input of the TDMS write Vi) should not be connected to other parts of the block diagram which may cause some "loading" effect. My other concern is to get the "read" to be quicker. Have tried the "MinimumBufferSize" property but didn't make a difference in the written file Size.

[BADGE NAME]

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Hi blessedk,

 

Glad to hear that your writes are running faster. As far as making the reads more efficient, though, I'd really have to take a look at your code. Could you post the vi or a screentshot of the read values that are taking a while?

 

Thanks!

Austin H.
Applications Engineering
National Instruments
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