Long time acquisitions using rs232gui/labview

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vaniaga
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Joined: Thu Aug 19, 2010 4:18 pm

Long time acquisitions using rs232gui/labview

Post by vaniaga » Thu Dec 09, 2010 6:29 pm

Hi,

I read in the Wiki:

" Watch out : When logging data for a long time usinga big buffer size, some data may be lost : As the matrix R is growing,Matlab reallocate memory when the matrix is growing. This memory allocation may take some time and for reason that are still unclear, Seral port lose some datas. "

How do i make long time acquisitions?
Labview is better solution than Matlab?

Someone could help me?
Thanks,

Vânia Almeida

LubinKerhuel
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Re: Long time acquisitions using rs232gui/labview

Post by LubinKerhuel » Thu Dec 09, 2010 11:44 pm

Hi Vânia ,

I updated the wiki page with a response to your question.
http://www.kerhuel.eu/wiki/Block/Interf ... b#Long_log

I hope it will help.

Lubin

LubinKerhuel
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Re: Long time acquisitions using rs232gui/labview

Post by LubinKerhuel » Fri Dec 10, 2010 12:27 am

Labview is also pretty goog for logging data. I think I already upload on the forum few labview file.
An exemple of the protocole is presented on my old (french) website : see http://lubink.free.fr/projelectro/Proto ... ew_FR.html

vaniaga
Posts: 4
Joined: Thu Aug 19, 2010 4:18 pm

Re: Long time acquisitions using rs232gui/labview

Post by vaniaga » Fri Dec 10, 2010 12:14 pm

Dear Lubin,

Now i can't test your solutions, but for the next week i hope to have news.
Thank you.

I send you my best regards.

Vânia Almeida

vaniaga
Posts: 4
Joined: Thu Aug 19, 2010 4:18 pm

Re: Long time acquisitions using rs232gui/labview

Post by vaniaga » Fri Dec 10, 2010 4:30 pm

Dear Lubin,

I have questions about realterm because in my project i need of long time acquisitions with real time vizualization.
If i receive the data using realterm, i can plot us in real time (like the start button of the rs232gui)?

Using the rs232gui interface (with the button load) is not possible.

Vânia Almeida

LubinKerhuel
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Re: Long time acquisitions using rs232gui/labview

Post by LubinKerhuel » Fri Dec 10, 2010 9:34 pm

Hi Vânia,

I am not sure to get it.
If you use a hyperterminel like realterm, you will record raw data into a file but you will not be able to see graph in real time ; only binary data that will appears on the screen with sometime beep (I think ascii 7).

To record data while seeing curve in real time, you could however use matlab with rs232gui with the Log.txt button to record raw data. Choosing a small value for values to be seen (You will see only the latest data, for exemple latest 10 seconds demending on the size of R and Rn (you should use R and Rn with equal size here).

The inconvenient of Matlab is only that the UART is accessed through Java that is less responsive. However, If it works, You will get your data without any data lost.
At the opposit, the good point of an hyperterminal is that it can be used on a computer were matlab is very slow. Thus you could use an old laptop for in the field recording.

If you want to see curve from the very beginning of the log, with a long log, you would rather use labview. I may have posted somewhere old Labview model that implement the protocole used here as rs232gui.

Lubin

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