Repeated data.

[Iskandark]

Hi. I have the same problem with my VI.  I use a WIKA P30 pressure sensure with a  DAQ NI 9209. Can someone help me? (I added my pressure.VI and an image of the excel data file output. After n seconds the program repeats the same data!).

Thanks!

[JÞB · Accepted solution]

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@Iskandark wrote:

Hi. I have the same problem with my VI.  I use a WIKA P30 pressure sensure with a  DAQ NI 9209. Can someone help me? (I added my pressure.VI and an image of the excel data file output. After n seconds the program repeats the same data!).

Thanks!

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I started a new thread for you. replying to a 5 year old thread with a new problem makes it difficult to follow what is going on 😄

Then fixed your code with less than a dozen keystrokes.

Select the collector Express vi, Ctrl+Space, Ctrl+R, Ctrl+U! Then deleted the Wait and the constant.  The DAQ Read will throttle the loop since it has to wait itself for samples to become available.

[Iskandark]

Thank you so much for your help!!! I wrote in an old place not to open a new one (I did not want to crowd the forum!) In this morning i will try the VI (with your advises).

[Iskandark]

Now i have another problem! (sorry but i'm completely new in LabView). (look at the attached figure)

Thanks to all for your help!!!

[crossrulz]

Buffer overflow.  This is because you loop is too slow.  What I typically suggest here is to use the Producer/Consumer architecture so that the saving of the data to disk is not slowing down your DAQ loop.  It would also help your case if you got rid of the Express VIs and used read functions, especially for the file IO so you can avoid constantly opening and closing the file.

[Iskandark]

Hello! Thank you for your reply. As i said before, i only start to use labview now and then i don't know what i should do. Are you telling me that i have to change all my VI? There is no possibility to solve this problem with the VI that i already have?

[Bob_Schor]

Learn 10 Functions in NI-DAQmx and Handle 80 Percent of your Data Acquisition Applications.  If you do a Web search with the previous sentence, you'll find an excellent White Paper that will show you how (relatively simple it is) to "change all your VI" and create an VI that will solve your problem.

Bob Schor

[Iskandark]

Thanks. i found it on the web. Now i'm reading it. 😉

[Iskandark]

I'm sorry, for my case it is better to use a PRODUCER / CONSUMER design pattern (DATA) or a PRODUCER / CONSUMER design pattern (EVENTS)? Thanks!

[crossrulz]

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@Iskandark wrote:

I'm sorry, for my case it is better to use a PRODUCER / CONSUMER design pattern (DATA) or a PRODUCER / CONSUMER design pattern (EVENTS)? Thanks!

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Data.  I am not a fan of the Events version since it is really turning into a Queued Message Handler (QMH), but that is another story.